Taking the Yangbi M_S5.1 earthquake on March 27,2017 as an example,according to the regional characteristics and signal-to-noise ratio requirements,the data from 1 January to 6 June, 2017 recorded by 6 stations with relatively complete recording were selected. The source waveform data of the airguns of the Binchuan earthquake signal launching platform were used to extract the travel time data of the stable seismic phases of the six stations,and to analyze the changes of the travel-time data before and after the Yangbi M_S5.1 earthquake. The results show that there are obvious time-varying changes in the stable seismic facies of the 6 stations before and after the Yangbi M_S5.1 earthquake,and the short-term transit time has good synchronization. There are small differences between the abnormal amplitude of the relevant stations and the abnormal time. The low-value anomaly process of the 6 stations before the earthquake was obvious,and the YUL station was the most significant. The morphological characteristics of the travel time before and after the earthquake are "double V",and the Yangbi M_S5.1 earthquake occurs at the end of the first "V" shape. After the earthquake,different stations with different orientations are affected by the earthquake,and there are differences in the fluctuations of travel time.