The invention provides a microwave thermogravimetric analysis device and combined system which comprises a microwave heating system, a temperature control system, a quality monitoring system and an external combined system. A microwave generator is arranged on the back of the device, and microwaves are transmitted to a stainless steel microwave resonator cavity through a waveguide. The temperature of a sample is monitored in real time by adopting an infrared thermometer, and the microwave output power is regulated, so that the set temperature needs are met. A through hole is formed in the bottom of the stainless steel cavity and connected with a lower electronic scale through a hollow cylindrical quartz tube; and the top end of a quartz tube bracket stretches into the stainless steel cavity. A quartz reaction bottle is arranged on the quartz bracket, the opening of the quartz reaction bottle penetrates through the stainless steel cavity, and the quartz reaction bottle is connected into a sample injection pipeline of the combined analysis system after valve diversion so as to perform online real-time analysis. The system disclosed by the invention is simple in structure and convenient to operate, microwave thermogravimetric analysis under different conditions can be obtained, thermogravimetric gas sample loss is effectively avoided, and complete sample composition information can be obtained.