It is essential to do seismic zoning of the historical earthquake epicenter and seismic intensity. A destructive earthquake occurred in Yongsheng, Yunnan in early 16th century. This is a doubtful earthquake. In this paper, we confirmed that the earthquake with M_S ≤ 7.0 occurred in Yongsheng County, Yunnan Province, China on August 31, 1502 or on June 1, 1511, by investigating the "Actual Records in the Ming Dynasty" and the "Local Chronicles Record". We found that the researchers adopted the records such as "stone doors destroyed, farm land sinking into the lake, etc. in the "Local Chronicles Record". These words conflict against the laws of nature. Another reason is that researchers mistook the Dali and Heqing earthquake as the Yongsheng earthquake, so they thought the historical earthquake with M_S7¾ occurred in Yongsheng County.