The invention discloses a vehicle speed control device and method. The vehicle speed control device comprises an environment sensing and integration module, a pedestrian jaywalking behavior cognition module and an automatic driving decision-making module, wherein the environment sensing and integration module is used for detecting the information of a jaywalking pedestrian in front of a running vehicle and outputting the information of the jaywalking pedestrian; the pedestrian jaywalking behavior cognition module is used for receiving the information of the jaywalking pedestrian and outputting the pedestrian's behavior cognition information according to the received information of the jaywalking pedestrian combined with the dynamic time series information and the interaction between the vehicle and the pedestrian; and the automatic driving decision-making module is used for receiving environment information and pedestrian's behavior cognition parameters, giving the current traffic speed of the vehicle, and outputting the current traffic speed of the vehicle. According to the vehicle speed control device and method disclosed by the invention, in the running process of the vehicle, the pedestrian target in front of the vehicle can be accurately recognized, the pedestrian's intention can be predicted, real-time judgment is performed, reasonable decision can be made, and autonomous recognition and decision-making of an autonomous vehicle can be realized when a pedestrian crosses the road, so that the vehicle can safely and smoothly give way to the pedestrian crossing the road.