Media playback is not supported on this device
Ma Long, Jike Zhang and Xu Xin defeated the Japanese trio of Koki Niwa, Jun Mizutani and Maharu Yoshimura 3-1.
China won all four table tennis golds available in Rio to take their total to 28 from the 32 available since table tennis' first Olympic appearance in Seoul in 1988.
Germany beat South Korea 3-1 to take the bronze medal.
China continued their dominance of Olympic table tennis as their men's team beat Japan in Wednesday's final.