Conformity crossing is one of the important potential safety hazards of pedestrian traffic． In uncertain traffic environments，the conformity effect of pedestrians play an important role in the whole process of the crossing decision of individual pedestrians． In this paper，the evolution rule for the crossing or waiting of pedestrians is de-duced based on the game theory after analyzing the factors influencing the interaction crossing，and a threshold model describing the crossing behavior is constructed to quantitatively evaluate the impact degree of reference group on individual pedestrian’s decision． Moreover，the interaction between the reference group and the individual is analyzed by using an example of interaction． The results show that the effect of reference group has a significant im-pact on the pedestrians’crossing behavior． This research expands and enriches the theoretical framework and tech-nique of pedestrian behavior analysis，and provides a scientific foundation for the establishment and implementation of high-performance safety measures for the crossing of pedestrians．