Abstract: With the help of advanced remote sensing digital technique and on the data basis of the topography map data and some GPS controlling points the DEMs in Tiantai village Xuanhan County Sichuan Province have been set up before and after the occurrence of superlarge landslide in on Sept 5th. 2004.And the ortho-image before and after the landside has also been acquired using high-resolution satelite image and proper image-disposal method. The slide direction and distance of each block of landslide has been calculated quantitativily by the method of interactive interpretation and determination of specific points and the total volume of the landside unity is estimated out to be about 2.3×10⁷m³. Based on the comprhensive analysis of the geological forming conditions of landside, the heavy rainfall event and the cution of the new road in the Tiantai slope are the main factors to trigger the occurrence of the Tiantai landslide.

Key words: Tiantai landslide, remote sensing digital technique, image process, triggering factor