Based on the time series and velocity fields of GNSS observation data in Yunnan from 2009 to 2020,the Kriging interpolation method is used to estimate the regional strain rate field. The time series of continuous reference stations are used as constrain,the block strain time series of the near-field area of the Yangbi M_S6.4 earthquake is obtained. The analysis results show that the Yangbi M_S6.4 earthquake happened in the high-value area of the maximum shear strain in the early stage and the tension-compression transition area of the high gradient zone of surface strain. The earthquake happened just after the gradual decrease of the regional strain accumulation rate. From the time sequence of the maximum shear strain and the first shear strain,the local area near the earthquake area is dominated by the accumulation of the right-lateral strike-slip strain of the NW-trending fault,and most of them show a continuous increasing trend. This is in line with the fault trend and fracture characteristics of the Yangbi M_S6.4 earthquake. There was a short-term strain trend turning phenomenon before the earthquake in the eastern area. This reverse acceleration anomaly reflects that the compression strain accumulation rate in the earthquake zone has increased significantly,and the strain accumulation is close to the critical point. The nonlinear adjustment in the rupture state accelerated the gestation process of the Yangbi M_S6.4 earthquake.