Abstract: Cell transmission model ( CTM ) is equivalent to discrete approximation from macro kinetics LWR model, which can be utilized to capture such traffic dynamics as traffic flow shock waves and traffic jam. Two parameters including cell length and cell density were introduced into the MCTM to avoid the uniform cell length limitation. Meanwhile, combining traditional fundamental diagram approach and three-phase traffic theory, the hysteresis loop characteristics were combined into the MCTM model. This paper employed the MCTM model to investigate the traffic congestion forming and diffusing process due to road capacity drop-down in the traffic incident. Simulation result shows that this presented model can effectively meet the modeling demands of reality traffic congestion evolution characteristics with incidents in urban expressway system.