The Antrim man, who had defeated John Higgins 6-2 in the semi finals, was an impressive 10-4 winner over Stevens in Sunday's decider.
Allen displayed terrific form on his return to Hainan Island as he raced into a 4-0 lead with scores of 52, 93 and 58 ahead of the mid-session interval.
Stevens had his chances, but his errors were capitalised on by the Antrim man although his opponent pulled it back to 4-2 helped by a break of 112.
But Allen took the next two frames, with a century break en route to a 6-2 lead.
Stevens again reduced the deficit as the players heading into the second session at 6-3in the Northern Irishman's favour.
When play resumed Allen won a safety battle to extend his lead before Stevens pegged him back to 7-4 with another 100 break.
However, Allen's safety play helped him into a 9-4 lead before a long red helped him to a clearance and the £85,000 winner's cheque.