Abstract: The reaction time of driver is the important matter of car following model research.The high precision GPS in vehicle was used to collect car following data in this paper.And the time serial car following data that reflecting driver behavior and vehicle moving character in real traffic flow was collected.The analysis method of driver reaction time in following vehicle was built especially aiming at deceleration regime.The probability distributing function and parameters of driver reaction time in following vehicle at deceleration regime were built,the function of relationship between driver reaction time and car following speed,and the function of relationship between driver reaction time and headway were built in this paper.