An innovative model based on brake heating for crash risk evaluation was proposed to quantitatively evaluate the driving risk of trucks on continuous downhill． First，considering the risk of chain accidents caused by the continuous reduction of truck braking performance，the brake heating of the brake hub was used to represent the key risk cause of the crash accidents，and the truck accident rate was used to represent the risk accident.Then，taking the continuous downhill in Ya'an-Xichang section of Beijing-Kunming highway as the research section，the risk cause and risk accident were quantified by numerical simulation of the brake heating，and the inner connection between braking temperature, temperature gradient and accident rate was revealed by correlation analysis.Finally，the crash risk measurement equation was constructed by using multiple nonlinear regression method to fit the surface function，and the crash risk evaluation model was established in combination with the risk classification criteria． The results show that the Cumulative Logistic function can better explain the changing law of the truck crash risk on downhill． The average error between the final model evaluation result and the actual accident is 0. 288，and the accuracy rate is 80. 87%． The evaluation model shows high accuracy and can provide reference for scientific decision-making in traffic safety management and control of continuous downhill sections．