First,we precisely relocated small earthquakes near the Lintan-Tanchang fault using a combination of the Hypo2000 single-event absolute positioning method and the double difference location method.The biggest advantage of the first method is that we can use a multi-velocity model,which is in line with complex underground structures and crustal heterogeneity.Relative to using only one velocity model in the traditional positioning method,the use of the multi-velocity model can improve the near-field positioning precision in a large part.Further,the biggest advantage of the second method is that it can eliminate the influence of the underground velocity structure on the relative position of the earthquake; subsequently,we can obtain an accurate relative position between the two earthquakes.Then,we divided the small earthquake distributed in the northern part of the Lintan-Tanchang fault into two segments,which are the east and west segments,respectively,according to the distribution of the relocated small earthquake,location of the fault,and distribution map of a medium-strong earthquake＇ s intensity.Further,in consideration of three similar focal mechanisms of the Minxian M5.2 earthquake on November 13,2003,Minxian M5.0 earthquake on September 7,2004,and Minxian M6.6 earthquake on July 22,2013,we combined the two segments together into one segment.Then,we separately estimated the strikes,dips,location,and corresponding errors of fault planes at different locations by simulated annealing and Gauss-Newtonian nonlinear inversion algorithms.It can not only search the global optimal solution but also estimate the parameter errors.Further,we can estimate the slip angle on the fault by using the parameters of the regional tectonic stress field after a large earthquake fault plane.Further,we inverted the rakes of the different fault planes by using local stress field parameters.The strike,trend,dip angle,and rake angle of the inverted fault plane were found to be NW-NWW,NE-NEE,71°～86°,and 102°～132°,respectively.Because of the small number of earthquakes in the study area,the error values of the strike angle,dip angle,and distance from the origin of coordinates for the inverted fault plane are too large.The error of the inverted dip angle is larger than that of the inverted strike angle owing to greater dispersion of small earthquakes on the fault vertical.Further,the error of the slip angle is much larger.The strike,trend,and dip of the fault plane inverted in this study are similar to those in previous studies and also similar to the fault parameters displayed on focal mechanism of the three medium-strong earthquakes.However,the fault types differ between this study and previous studies,which are separately dextral and sinistral strike slip.Further,the fault-type considered in this study differs from that displayed on the focal mechanism of the three medium-strong earthquakes.It was primarily concluded that an inversion error of the regional stress field parameters exists because of focal-mechanism solutions of small earthquakes,and this error influences the inversion error of the rake angle on the fault plane.However,the inverted slip angle in this study is comparable to that reported in previous studies.