In order to evaluate the safety and traffic efficiencyof different U-turn modes aturban road intersections， the U-turn behaviors of vehicles weresimulated using microscopictraffic simulation methods based on VISSIM simulation modeland traffic safety alternativeevaluation model(SS AM) .Based on the average queue length，average delay time， averageparking times， traffic conflict types and numbers， the safety and traffic efficiency of threetypical U-turn modes on urban roads were evaluated.There sults show that at any drivingspeed， the U-turnmode before the stop line produces the leaast traffic conflicts， and thequeue length and delay time of vehicles in the U-turn mode ini side the intersection are theleast.Comprehensive evaluation shows that when the vehicles ppeedislowerthan50km/h，the U-turn mode at the intersection can not only significantlyreduce the number of trafficconflicts， but also have less impact on the vehicle traffic effic iency at the intersection.It is the best of the three U-turn modes.When the vehicle speed is higher than 50km/h， theU-turn mode before the stop line is the best.Through comparison and analysis of differentU-turn modes， it is suggested to select an optimized U-turn mode as the U-turn mode atthis intersection by referring to the vehicle driving speed.