Abstract: The “5·12” earthquake has caused great damage to the ecological environment of Wenchuan County. Quick and effective assessment of the ecological environment quality in the earthquake-stricken areas is an important basic work for post-disaster reconstruction. Based on TM and OLI data and principal component analysis technology of ENVI platform, the remote sensing ecological index (RSEI) of three periods in the study area is obtained, which can be used to analyze the changes and restoration of the ecological environment quality in the study area from 2003 to 2017. The results showed that: (1) From 2003 to 2017, the ecological environment quality of Wenchuan County was mainly moderate or above, and the proportion of moderate or above grade was 90.21%, 82.01% and 94.65% respectively in the three periods. (2) The average RSEI index of the three periods was 0.627, 0.617 and 0.716 respectively, so the ecological environment quality experienced the process of no recovery to recovery and improvement, and the ecological environment quality at the end of the study exceeded the beginning of the study. (3) From 2003 to 2017, the area transfer of the three grades of poor, moderate and good in the ecological environment quality of Wenchuan County was obvious, while the two grades of bad and high did not change much. In T1 period, moderate and good grade were transferred to lower grade; in T2 period, poor, moderate and good grade were transferred to higher grade; in T3 period, except high grade, the other grades were mainly transferred to higher grade. (4) In the area between 1 498-4 466 meters above sea level and 15-63 degrees of slope, the recovery of ecological environment quality is the most obvious.