Wang lost to Ryu Seung-min in the Athens final in 2004
China's world number one Wang Hao booked his place in the men's table tennis singles final with a 4-1 win over Sweden's Jorgen Persson.
Wang, who lost the Olympic final in Athens in 2004, overcame a battling Persson 11-9 11-9 9-11 11-7 11-9.
His victory means that China are guaranteed gold as Ma Lin edged Wang Liqin in the other semi-final.
Ma Lin, the world number two, survived a thrilling tie to eventually win 11-5 11-9 11-9 10-12 3-11 11-8.
Ma won the first three sets before Wang Liqin came storming back to win the next two, and he held off a ferocious charge from his team-mate in the sixth game to reach the final.
In the other last-four tie, Wang Hao won the first two sets before Persson hit back in the third as his opponent seemed rattled by an umpiring decision.
But Wang settled in the fourth, winning some lengthy rallies, and although Persson, the 42-year-old 1991 world champion, levelled at 9-9 in the fifth, Wang was too strong.
"We lost the men's singles title four years ago and to have regained it in 2008, we are very excited," said head coach Liu Guoliang.
"Table tennis is our national sport. We have shown this to the crowd today."
China have already won the men's and women's team titles in Beijing and all three medals in the women's singles.