Abstract. Distant lead is one of the ways to eliminate the left turn of the intersection, and the determination of the length of the U-turn is the key to determining the success of the method. For the determination of the optimal length of the far-lead turn-around, the main traffic parameters are determined on the basis of the existing statistic data, and then the VISSIM is used to analyze the intersection in peak period and no-peak period. Finally, the simulation results are statistically analyzed by MATLAB, and the shortest distance of the simulation travel time is taken as the optimal lead length. The results show that the optimal length of the far-lead is obtained in the peak period and the peak-peak period. Under the hypothesis parameter, the optimal length of the U-turn is 300m in the peak period and 250m in the non-peak period; through theoretical analysis, the peak length of the peak is 297.61m, and the peak length of 254.21m.