A calculation method for separating the influence of key factors on crop phenology based on a crop growth mechanism model is provided. By adjusting the accumulated temperature parameters of crop mechanism model varieties with the phenological data observed in the field, crop growth processes under different scenarios are simulated by a crop phenology model to separating the influence of key factors such as climate change, sowing date adjustment and variety change on crop phenology. The method can directly separate the influence of each key factor on crop phenology and is of great significancefor crops in coping with climate change, guiding variety breeding and improving a sowing system.