The safety of waste dump projects of mountainous expressways is related to environmental protection，water and soil conservation，highway building protection，and downstream environment-sensitive point protection，so it is necessary to put forward safety assessment methods.Based on the data analysis of 1 369 waste dumps in Yunnan Province，the safety risk factors of the waste dump engineering were proposed and summarized as five primary indicators，including site selection and design factors，construction factors，regional geological factors，external influencing factors，and data integrity factors，and 18 secondary indicators were further put forward.The group decision-making analytic hierarchy process （AHP ） model was established，and the weight of secondary indexes was determined by 64 technical experts.The technical index system of safety risk assessment of the expressway waste dump engineering was constructed，and the risk classification standard was set.With a waste dump engineering of Dali —Lijiang Expressway as an example，the safety risk assessment system of the waste dump was tested，which proved that the assessment system was simple and easy to implement.The weight optimization needs the support of big data in practice，and the assessment system is suitable for promotion and application in the waste dump engineering of mountainous expressways.