The invention discloses an ultrahigh-speed aircraft cabin thermal environment testing device and method. The ultrahigh-speed aircraft cabin thermal environment testing device comprises a testing tool component, a cabin component and an under-deck component. The testing tool component comprises a plurality of heating membranes which are attached outside the cabin component and manufactured according to the outer wall of the cabin component. The multiple heating membranes completely wrap a thermal insulating layer in a fit mode. The ultrahigh-speed aircraft cabin thermal environment testing method includes the step of preparation of a detection platform, the step of coating of the inner thermal insulating layer, the step of wrapping of the heating membranes and the step of measurement. According to the ultrahigh-speed aircraft cabin thermal environment testing device and method, the heating membranes are adopted for heating, the thermal environment in complex cabins of an ultrahigh-speed aircraft are well simulated, and then thermal design in the cabins can be detected.