The three-times world champion led off with an Olympic record lift of 143kg with his third attempt in the snatch and all but assured himself of gold when he hoisted 167kg in his second attempt at the clean & jerk.
On his third attempt he had 172kg loaded onto the bar, which would have broken the total world mark of 318kg he set at the 2019 world championships in Pattaya, Thailand.
The 31-year-old got the bar onto his chest but, despite stretching every sinew, his right leg buckled when he tried to raise it over his head and he had to let it drop to the mat.
“I’m really happy that I’m competing at this Olympic Games. The atmosphere is really great, and I really enjoyed the competition,” said Li.
“I’m getting older and older, so this might be the last time I compete, but I’m still looking forward for maybe the next time. I would like to have one more gold medal for my country.
“I don’t have any concrete idea right now. I just want to enjoy the moment. I won the gold medal today,” the 31-year-old added.
The competition started after a half-hour delay at a packed Paris Expo divided evenly between noisy Chinese and American fans.
Thailand’s Theerapong Silachai took a surprise silver medal in a thrilling finish after lifting an impressive 171kg in the clean & jerk for a total of 303kg.
American Hampton Morris finished third for bronze with a total of 298kg after failing in his last attempt at 178kg in the clean & jerk, a lift that would have bettered the world record of 176kg he set in Phuket, Thailand in April.
“On the clean and jerks, I felt really great in the back room. That first attempt up on stage – I’m mad,” said Morris.