Each trip has many factors in urban envioronment. No matter what the degree polluted is, under accumulating over a long period, the climate is suffered and destroyed. It takes even decades of more than ten years to retume. This study uses such three parts as urban transportation envioronment, personal cognition, and traffic mode choice to construct the SEM equation between traffic mode choice and CO2 mitigation. There are some results in this study. The tax rate rise and the public transports influence traffic mode choice in urban transportation environment. Then, personal preterences also effect urban traffic mode choice in personal cognition. Finally, the primary influence for people is the rise of oil price. When oil price rises, people will reduce the usage of private traffic mode.