Autopilot is a vehicle that can operate autonomously and safely without the driver's operation. The analysis of criminal responsibility after traffic accident should be divided into pure automatic driving and conditional automatic driving. Pure autopilot car traffic accident, based on the "cost income" considerations, should not be the vehicle itself as the main body of criminal responsibility. Since the driver acts as a passenger and does not participate in the vehicle operation from the beginning, the designer becomes the main body of responsibility. The probability theory of "possibility" should be adopted for the causal relationship between the accident behavior and the result. The driver of a conditional autopilot is the principal responsible person after a traffic accident. According to the "legal condition doctrine", the designer, the producer or the seller will bear the fault of the product fault within the possible scope according to the foresight possibility.