It is now seven wins from 12 races this season for Vettel who holds a 92-point cushion over team-mate Mark Webber after the Australian finished second for the second successive year.
After his 17th career win, Vettel is in such a commanding position he has now scored more points so far this season - 259 - than he did in winning the title last year with 256.
The result was also the 10th one-two for Vettel and Webber, making them the fourth most successful pairing in F1 history.
Jenson Button produced a storming performance to claim third from 13th on the grid, but it was another wretched race for McLaren team-mate Lewis Hamilton as he crashed out on lap 13 following a collision with the Sauber of Kamui Kobayashi.
The two Britons are now 110 and 113 points respectively adrift of Vettel, with Ferrari's Fernando Alonso 102 down after he finished fourth in his Ferrari.
Come the end of the Kemmel straight on lap 13, Hamilton's race - and effectively what was left of his title challenge - was wrecked.
Over the opening 12 laps he had occupied all positions from first to eighth for a variety of reasons, but at that prime stage had just claimed fourth from Kobayashi.
Heading down Kemmel, the Japanese attacked Hamilton and, as they approached the right-hander Les Combes at the end of the straight, the Sauber's front-right tyre hit the rear-left on the McLaren.
The contact immediately sent Hamilton into a spin, and at such high speed he ploughed nose first into a barrier, then careered through a polystyrene advertising hoarding before continuing on to a halt.
After a few moments to compose himself, Hamilton finally emerged from the cockpit of his car, with the accident prompting a safety car due to the amount of debris.
Assessing the incident, Hamilton said: "I'm not really quite sure what happened. I hit the wall pretty hard.
"As far as I was concerned I was ahead of whoever I was racing and then I was hit by them.
"We were struggling, we were massively slow on the straights and I guess that's why we were in that position, although we might at least have got a podium."
Prior to that it had been a frenetic beginning, with Nico Rosberg the leader at the end of the first lap after starting from fifth.
At the opening La Source hairpin there were a number of collisions, the most notable of which saw Bruno Senna, on his debut for Renault, slam into the side of Jaime Alguersuari's Toro Rosso.
The damage for Alguersuari was substantial, in particular a broken front-left suspension that forced his retirement midway through the opening lap, and a cruel blow after starting a career-high sixth on the grid.
The change of positions that followed was then staggering, notably along the Kemmel straight where the DRS (drag reduction system) could be deployed.
In some respects it was all too easy to overtake, that was until Kobayashi and Hamilton collided, opening the door for Red Bull to take advantage given their complaints prior to this race regarding degradation to their tyres after qualifying.
Vettel nipped in to take on fresh tyres, and from that moment it was a case of managing the situation after lining up third behind Alonso and Webber once the safety car exited after 16 laps.
The 24-year-old German swiftly made his move on both, and once in the lead he lost it only once more, albeit exceptionally briefly to Button following his third stop.
Beyond that it was a cruise to the line for Vettel, while Webber passed Alonso late on to bag second, with Button doing likewise to the Spaniard on lap 42 to net third.
That underlined it was a case of what might have been for Button in light of qualifying woes yesterday when "a miscommunication" led to his lowly grid spot.
Behind the leading quartet Michael Schumacher claimed a stunning fifth from last on the grid to appropriately mark the 20th anniversary of his F1 debut.
Mercedes team-mate Nico Rosberg was sixth, followed by Force India's Adrian Sutil, Vitaly Petrov in his Renault and the Ferrari of Felipe Massa.
Williams' Pastor Maldonado grabbed 10th to net his first point of the season, finishing just ahead of Paul di Resta in his Force India.
"We had some tyre concerns beforehand, and both of us (referring to team-mate Webber) stopped early in the race," said Vettel.
"But surprisingly the pace was good, I was able to reclaim the lead (after losing it early to Rosberg), and after the safety car it was more about management than usual.
"The car worked brilliantly, so I'm very happy with the result, in particular with how we managed the tyres."
Webber's race was compromised by what he described as a "shocking start" due to the anti-stall kicking in as he began to set off.
"That was very disappointing, and we were on the backfoot from there," said Webber, who celebrated his 35th birthday yesterday.
"But all in all, the way the teams handled the problems is a credit to everyone. In the end we got a good result.
"I would loved to have won, but it was still an enjoyable race."
In the middle of the pack, Button described turn one at La Source as "mayhem", adding: "Di Resta hit my rear wing so I lost the rear-wing endplate.
"Then driving through Eau Rouge somebody's front wing came off and hit mine, and it also knocked a off a wing mirror.
"After that I had a good race, so overall a podium is pleasing, but to see a Red Bull one-two is very disappointing.
"The balance of the car here was phenomenal because it felt like we had improved from Hungary (where he won).
"Who knows what would have happened if we had qualified well, but we've only come away with 15 points, so we have to make sure we change that at the next race."