The left-handed opener needed 69 more runs to reach the landmark when the Proteas were sent into bat in Pune.
And having completed a 62-ball fifty, including three fours and two sixes, De Kock broke through the 500-run barrier with a legside boundary off recalled paceman Tim Southee.
At that stage, South Africa were 154-1 off 29 overs.
De Kock's latest innings followed scores of 109 against Australia and 174 against Bangladesh, with South Africa having lost just one of their six games at the tournament so far.
De Kock, who is currently averaging over 83 at this World Cup, has said he plans to quit one-day international cricket when this tournament is over.
He leads the event run chart ahead of Australia's David Warner (413) and New Zealand's Rachin Ravindra (406).
