Transpiration water is the main mode of plant water consumption. This study takes Larix principis-rupprechtii Mayr in the north of Liupanshan Mountains as a study object. The water consumption characteristics of Larix principis-rupprechtii Mayr are studied using advanced SL??F technology and then the relationship between transpiration rate and environmental factors is analyzed. A regressive model is constructed through analyzing the meteoric factors. The fuzzy transpiration model based on Matlab is designed and simulated. Results indicate that air temperature and air relative humidity directly affect transpiration rate.Solar radiation intensity can affect the transpiration rate of Larix principis-rupprechtii Mayr by influencing air temperature and air relative humidity .