A strong earthquake occurred in the region of Yinchuan on the May 13，1477.Due to the earthquake happened at the edge of Tenggeli desert，which is a desolate and uninhabited place，historical records about this earthquake is limited.On the basis of historic documents，the magnitude of this strong earthquake was examined to be M=6 1/2，the epicenter of the west of Yinchuan（38.5°N），106.3°E， the epicentral intensity of Yinchuan was Ⅷ in all previous publication of the catalogues of earthquake in China.However，some experts have questioned the identification results，we also have problems with the magnitude and epicenter.In the paper，based on the same historical earthquake data，we use the empirical formula for estimation of seismic magnitude and elliptical attenuation of seismic intensity and some interrelated modern earthquake data；by the methods of estimating and comparing，we reanalyze the magnitude，it’s epicenter and the seismic intensity of several region of the 1477 strong earthquake. In our opinion，we recommend that the magnitude of the earthquake should be identified as M=7 1/4 ，the epicenter should be located in the east of Minqin（38.40°N，104.36°E）.In addition，the epicentral intensity of Yinchuan is advised to be Ⅶ,and Zhangye is Ⅵ. Finally，combining with the proposal epicenter location，we simply discuss the seismogenic tectonic background of 1477 earthquake.