Core differential strain analysis method is one of the primary means of in-situ stress measurement in WFSD. This paper describes the principle and data processing method of in-situ stress measurement by differential strain analysis(DSA) in WFSD-1.And the stress profile is established with depth in the hole. Test results show that the stress states of the upper and lower plate in the Yingxiu-Beichuan fault are significant differences. Regional in-situ stress not only increases with depth, but also concerns with the geological structure, rock physical properties and other factors.