Wireless Sensor Network has been well developed in landslide monitoring field. Although the progresses, the threshold for prediction is still not easy to acquire and verifying. After geotechnical experiments and analytical analogy, a composite index including tilt speed, daily precipitation, soil water content were suggested. By the rain season of this year, the warning thresholds have been successfully applied in Chengdu, Wenchuan earthquake stuck area, which encountered with heavy storm this year.