Abstract: With the continuous development of digital seismic networks and the application of mobile seismic array observation technology, arrival picking of seismic phases and detection of seismic events are paid more and more attention. Based on the preliminary results obtained by STA/LTA and AIC method, this paper combines the Delaunay triangulation and the maximum travel-time difference between stations to reduce the influence of noise. The arrival time predicted in every station is obtained by earthquake location on the basis of the preliminary results. Moreover, in accordance with the feature of low signal noise ratio of microseismic events, this paper developed a new phase picker which is based on the polarization. According to the results of STA/LTA method and AIC method in the time window, it automatically selects the appropriate values as arrival times. The analysis and processing of 304 seismic events recorded by Xichang portable seismic array in 2013 demonstrate that the new method proposed in this paper has stronger earthquake detection capability and higher seismic picking accuracy than traditional methods.