Through the force analysis on straddle-type monorail vehicle bogie and the track beam, the safety performance evaluationindexes of straddle-type monorail vehicle through curve were studied, combined with railway and vehicle safety performance evaluationindex. The overturning coefficient of vehicle was revised, and the lateral force of wheel and rail was defined based on the wheel railsafety; and the evaluation method of anti derailment stability was redefined, and it is used to analyze and evaluate the safety performanceof straddle-type monorail vehicle through the S-shaped curve at normal operating speed (36 km/h). It shows that straddle-type monorailvehicle through this curve has good safety performance.