The comparison of the seismic parameters of earthquakes in 1306 and 1622 in Guyuan in different directories and the references to historical data, combined with the field survey, reveal the two earthquake sites of Chaonaqiu and Magangpu. The comprehensive analysis of the historical data and the site investigation help draw the conclusion that that the epicenter of Guyuan in 1306 should be 35.9o N, 106.3o E and the epicenter of Guyuan in 1622 should be in 36.5oN south.