In this paper, a model based on BP neural network with fitting the relationship between car speed and wind speed is proposed for the problem of side wind on the safe driving of cars on bridges. [1] The model analyzes the car speed and wind speed according to the gradient descent algorithm, and adjusts the connection weights and thresholds of neurons in each layer according to the statistical results combined with the learning efficiency [2] . At the same time, this paper derives the maximum safe speed of the car when turning as the training set by constructing the physical and mathematical models of the car. After 4 epoch training, the mean square error (MSE) of the training set is obtained, and the loss of the test set is 0.16521.