The invention relates to a testing device for simulating spontaneous combustion and fire extinguishment processes of coal. The main structure of the testing device is composed of a reaction kettle, a heating layer, an asbestos thermal insulating layer, a microwave generator, a base, a kettle cover, a gas filter screen, an intake valve, an intake pipe, an exhaust valve, an exhaust pipe, a temperature sensor, an electric cabinet, a control panel, a display screen, an indicator lamp, a power switch, a microwave controller, a measurement regulator, a control circuit board, an oxygen bottle, a nitrogen bottle and a lead, wherein the reaction kettle is employed for heating and preserving heat; the temperature sensor acquires information, and testing indicator gases in the spontaneous combustion and fire extinguishment processes of coal; oxygen is introduced to simulate spontaneous combustion, while the nitrogen is introduced to perform a fire extinguishing test, so that the change rules of the indicator gases of the spontaneous combustion and fire extinguishment processes of coal are obtained; as a result, scientific data is provided for spontaneous combustion fire prevention and extinguishment; besides, the device is advanced and rational in design, compact in structure, safe, stable and reliable, convenient to operate and use, widely applicable to many test and experiment items, high in test accuracy and short in test time.