Lhasa tourism drives Lhasa's economic development and also brings a considerable burden to Lhasa's transportation, so solving the problem of traffic congestion caused by the increase of non-motorized traffic flow at the intersection in Lhasa is of great significance to the development of Lhasa's transportation. In order to solve the problem of non-motorized vehicles turning left at the intersection and alleviate the traffic pressure in Lhasa, this paper constructs a multi-phase signal timing optimization scheme based on the Webster timing method model, and takes the intersection of Dangre Middle Road and Niangre Middle Road in Lhasa as an example, and through the simulation of Vissim simulation and delay calculation analysis, it is concluded that the multi-phase signal timing model constructed in this paper is better than the traditional four-phase signal timing in terms of the traffic organization behavior of the left-turning of non-motorized vehicles. Traditional four-phase signal timing, this paper on the six-phase signal timing scheme research on the future intersection of non-motorized traffic capacity and the intersection of the level of service to improve the multi-phase signal timing scheme to provide a multi-phase signal timing scheme optimization ideas.