In order to find a suitable intercropping model for alpine tea plantations and explore the effects of different intercropping crops on the occurrence of major leaf diseases in tea plantations, field experiments were performed to identify the main types of leaf diseases in tea plantations in northwest Sichuan. Through the investigation and study of the disease occurrence in tea-soybean, tea-maize, tea-plum, tea-Magnolia officinalis intercropping gardens and pure tea garden, the leaf disease occurrences in different tea gardens were compared and analyzed. The results show that the main diseases of tea plantations in northwest Sichuan were tea blister blight, tea anthracnose, tea brown blight, tea bird’s eye spot and tea red leaf spot. Among the four intercropped crops, soybean and maize were the ideal intercropped crops. The lowest incidences of tea blister blight and tea anthracnose were found in the tea-soybean intercropping system. Compared with the control, the incidences of tea blister blight and tea anthracnose decreased by 85.12% and 74.34%, respectively. The incidence of anthracnose in tea-maize intercropping system was reduced by 49.76% compared with the control. However, the average incidence of tea blister blight and anthracnose in tea-Magnolia officinalis intercropping garden were 27.82% and 51.67%, which were 10.50 and 1.73 times higher than those in the pure tea garden. The soybean and the maize could replace Magnolia officinalis as an ideal intercropping crop in alpine tea garden. Intercropping soybean could significantly reduce the occurrence of diseases and thereby losses.