China Earthquake Administration has installed a strain monitoring network of 40 sets four-component borehole strainmeters. One strainmeter located in Sichuan Guzan seismic station has recorded distinct tidal distortion and strain abnormity during the seismogenic process of Wenchuan and Lushan strong earthquakes. These abnormal changes basically met the three criteria of earthquake precursors, thus they were considered to be strain precursor of the seismogenic process of two strong earthquakes. In this paper, the related record information was analyzed, which would provide reference for the subsequent strong earthquake prediction.