To solve the problems of low efficiency of manual weighing of activated carbon and inability of online weighing in spark extinguisher detection,based on the national standard GB13365-2005,this paper proposes a design of an automatic detection system for motor vehicle spark extinguishers.The system is designed with an automatic weighing device,which can realize the automatic real-time weighing ofactivated carbon weight during the testing process.For the errors caused by airflow during the weighing process,this paper adopts a software approach for real-time automatic calibration.Firstly,the Kalman filter algorithm is used to denoise the training data,and then the third spline interpolation is used to fit the noise reduction data to construct the error compensation model.The actual online test results show that the weighing error of this system can be controlled within 1 g after compensation,which meets the requirements of practical use scenarios.