Abstract: To clarify the applicability of CARAH warning model against potato late blight in Sichuan spring potato, CARAH warning model was used to monitor occurrence of potato late blight and provide control measures in different altitudes in Sichuan. The results showed that the higher the altitude, the lower infection degree of potato late blight. The major infection degree was mild when the altitude was more than 3500 meters above the sea level, while the major infection degrees were moderate and severe when the altitude was less than 3500 meters above the sea level. Concerning the primarily infected plants, different varieties had different infection cycles of potato late blight, and the same variety at different sites had different infection cycles too, which might be related to the difference ofPhytophthora infestans in different sites. Five fungicides showed good control effects on potato late blight under CARAH warning and had no significant difference.