Uchimura became the first man to win three all-around world championships with a stunning performance Friday. Saturday he improved on his competition-best score of 15.566 from Friday with a 15.633 in the floor exercise, including an 8.933 in execution.
He also won the event at the 2010 World Championships.
Zou Kai of China took the silver with a score of 15.500 and the bronze medal went to Brazilian Diego Hypolito.
American McKayla Maroney won the women's vault with a score of 15.300, which was well ahead of silver medalist Oksana Chusovitina of Germany, who totaled 14.733. Vietnam's Phan Thiet was third at 14.666.
Russians won the gold and silver in the uneven bars. Viktoria Komova finished first at 15.500 and Tatiana Nabieva was second with a 15.000. China's Huang Qiushuang took the bronze at 14.833.
Hungary's Krisztian Berki won the pommel horse gold with a score of 15.833 with France's Cyril Tommasone (15.266) taking the silver and Britain's Louis Smith (15.066) in third.
Chinese gymnast Chen Yibin claimed the championship in the rings, scoring 15.800. The silver medal went to Brazil's Arthur Nabarrete Zanetti (15.600) and Japan's Koji Yamamuro (15.500) finished third.