DCP, which made the original bid in September, has roped in the two other investors and sent a revised bid of $79.05 per share to take 51job private.
The offer represents a deal value of about $5.33 billion, according to Reuters' calculations.
U.S-listed shares of 51job, which have fallen 10% after the first takeover bid, were up 14.3% premarket on Tuesday.
A special committee will continue to evaluate the proposal in the light of the latest development, 51job said.
Founded in 1998, 51job provides human resources services, including initial recruitment to employee retention and other career-related assistance, in China.
(Reporting by Eva Mathews in Bengaluru; Editing by Shinjini Ganguli)