di-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang=EN-US>The MS8.0 Wenchuan Earthquake has caused severe damage to the Longmen mountain areas. It is of great significance to evaluate soil erosion in a small watershed for post-earthquake reconstruction and soil and wter conservation. The results indicated that soil erosion in all the small watersheds had worsened. The distribution of soil erosion severity decreases from westnorth to southeast. The average altitude and average gradient showed positive correlation to ISES in small watersheds before and after the earthquake, furthermore, the average gradient contributed to the change of ISES more.