Based on China naturalistic driving data, a driver model for emergency braking was set up and the general characteristics of driver’s braking behavior were analyzed. The results show that the driver’s emergency braking response time is related to the urgency of emergency scenario. By taking the inverse of time to collision 0.2 s-1 as dangerous trigger threshold, the driver’s emergency braking reaction time is the normal distribution of mean 0.5 s. The maximum braking deceleration do not vary with the urgency of the scenarios. The maximum braking deceleration jerk increases with the urgency of the scenarios.