Yao's best effort of 13.05m (1055 points) secured her victory ahead of compatriot Yang Yue. Germany's Michaela Floeth was third.
Ukraine's Andrii Holivets threw a European record to win the men's Shot Put - F11/12, his mark of 16.25m equating to 991 points.
Russian Vladimir Andryushchenko won silver ahead of Australia's Russell Short.
China's Liu Fuliang won the men's Long Jump - F46 title with a leap of 7.15m, France's Arnaud Assoumani getting silver and Azerbaijan's Huseyn Hasanov bronze.
Germany's Sebastian Ernst Klaus Dietz took the men's Discus - F35/36 title, with Ukraine's Oleksii Pashkov second and China's Wang Wenbo third.
On the track, Great Britain's David Weir, who won the 5000m - T54 at the Olympic Stadium last night, began his bid for a second gold medal of London 2012 by safely qualifying for the final of the 1500m - T54 .