Barcelona forward Neymar was given a rough ride by the tough-tackling Korean defence but put the visitors in front just before half-time, before
Chelsea midfielder Oscar made certain of victory for the five-time World Cup winners, who are hosts of next year's tournament.
Brazil controlled the match from the early stages, with Jo seeing a shot well saved in the 13th minute by Jung Sung-ryong.
Oscar shot over the bar 10 minutes later, and the opportunity from which Neymar made the breakthrough came after the striker was brought down on the edge of the South Korea penalty area in the 42nd minute.
He took the subsequent free-kick and fired the ball beyond the goalkeeper.
The second goal came early in the second half as Paulinho played in Oscar who took on goalkeeper Jung and shot into the inviting goal.
Brazil coach Luiz Felipe Scolari brought on Lucas, Hernanes and Maxwell to give his squad the opportunity to impress.
Neymar shrugged off the rugged attentions of the home defence, saying after the game: "They are part of me, like a friend of mine.
"They are part of the game. I only don't like bad intentions, but fouls are part of football."
He told Globoesporte.com: "We are all happy because we are improving. It is not easy because of a lack of time but we are happy."
Scolari will unveil his World Cup squad on May 7 and will have four more matches in which to test his players.
They play Zambia on Tuesday in China, before facing Honduras on November 16 in Miami, Russia on November 19 in Toronto, and South Africa on March 5 in Johannesburg.