A test device and a test method for dynamic characteristics of a spring-loaded safety valve are mainly used for testing opening, emission and return seat characteristics of the safety valve. The air pressure stabilizer is used for stably adjusting gas pressure in a pressure vessel. The quick start and stop device is used for controlling opening and closing of the pressure vessel. The pipeline gas mass flow detecting device is used for detecting the mass flow of the gas in a pipeline. The safety valve stem displacement detecting device is used for detecting the displacement change of a safety valve stem. The acquisition system is used for collecting, processing and saving experimental data. The device of the present invention has simple structure and high precision, and provides guarantee for the test of the dynamic characteristics of the safety valve.