The invention discloses a safe flow simulation method based on a CAN (Controller Area Network) bus. The method comprises the main steps of collecting real-time data on the CAN bus of a real system; packaging real-time messages and real-time data on the CAN bus of the real system and the time information of the real-time data into real-time data packets; defining a real system operation scene model, and forming flow fragments of the work site of the real system; according to state fragment and combination of the state fragments, combining the real-time data packets to form operation scene data; and according to the simulation process of the simulation system, sequentially outputting the operation scene data, or responding to the simulation process, and outputting the corresponding operation scene data. The on-site real data is decomposed from control flows in a simulation control strategy and a real control process and forms matching relations with the same, thus the strategy step and the control flow are played back and matched by the real on-site data packets to form data packets, flows and scenes with different details and ranges. A data fusion and processing interface during a simulation process is simplified. The invention also comprises a safe simulation system.