Abstract: To identify the congestion of signalized intersection upstream in snow and ice conditions, a method based on the value of the critical dissipation queue length was proposed. According to car driving theory and vehicle driving characteristics in the congestion interval, driving process of the critical traffic congestion was divided into acceleration, uniform speed and deceleration processes. Congestion identification model at signalized intersection in condition of snow and ice was formulated based on analysis of passing process of queuing vehicles. Upstream congestion threshold was calculated with the calibration parameters under different situation. The model was verified using the actual survey data of an intersection in Harbin city, and show the good fitness of model results and traffic flow in practice.