Abstract: On April 22, 2013 17:11, an M5.3 earthquake occurred in Inner Mongolia Tongliao city (122.4°E, 42.9°N). The earthquake and earthquakes before and after the earthquake in the source region are firstly located using the Hyposat and then relocated using the double difference fine positioning inversion method. On basis of the relocated accurate epicenters, the parameters of the source fault of the M5.3 earthquake are inversed; at the same time, the focal mechanism solution of the earthquake is calculated using the CAP method which is used to infer the crustal stress field and geological structure in the region combining with the source fault parameters. The results show that the earthquake is related to the activity of the Yangxumu buried fault.