When the vehicle passes through the remote sensing equipment, the light shielding triggers the test, and after the detection light emitted by the main engine passes through the exhaust smoke, it is transmitted back to the host to receive the sensor through the reflection end, and the concentration of the smoke is calculated by using the signal difference of the detection light absorbed by the exhaust plume; the detected vehicle will be photographed by the camera as a record in order to match the vehicle license plate number and make the post-processing work more efficient. The speed and acceleration of the vehicle are accurately measured by the laser speedometer based on the multi-point measurement principle or the radar multi-point measurement principle, which is used to calculate the VSP to analyze the vehicle driving state. The automatic calibration device is used to automatically / manually calibrate the tail gas measurement module of the main engine of the system, and the standard gas cylinder is used as the calibration gas, once every 2 hours to ensure the accuracy of measurement.