In order to provide decision for drivers at urban road crosswalk, experiment of driver’s decision and risk perception was conducted. And driver’s perceptional risk and decision were analyzed. Changing rule of driver perceptional risk with speed variation was given, and driver’s decision loss function was put forward. Collision risk probability model was established based on probability theory. Loss for delay and collision risk was calibrated respectively. The redult is that driver should keep uniform speed or accelerate at low speed, and deceleration will increase loss; at medium speed, there is no evident difference for driver among acceleration, deceleration and keeping uniform speed, but keeping uniform speed is better; at high speed, the best solution is keeping uniform speed.