More than 2,000 robots are taking part in the Beijing Robot Games, where humanoid machines race, play football and perform tai chi.
At the National Speed Skating Oval on Sunday, Tiangong Omni-04 won the 400-metre race for smaller robots in 45.66 seconds, while others fell or stopped before reaching the finish.
The five-day competition is designed to test skills that robots may eventually need in real-world settings.
Engineers cool the machines after races and watch closely as they walk, run and take on physical challenges.
At the tai chi event, robots attempt kicks and aerial turns. Engineers say such trials can help assess stability, joint power and overall system performance.