The utility model relates to an indoor self-purification self-checking device, and belongs to photochemistry self-purification experimental apparatuses. The indoor self-purification self-checking device comprises a sealed box. A gas inlet is formed in one side of the box. A gas outlet is formed in the other side of the box. A hollow dual-layer cold trap used for containing a light source is arranged in the center of the box. A water inlet and a water outlet are formed in the opening end of the hollow dual-layer cold trap. The indoor self-purification self-checking device further comprises an experimental plate installed in the box and used for being coated with a wall coating used in a room to be detected. By means of the indoor self-purification self-checking device, gas to be detected can be input in a sequencing batch or intermittent mode, the gas outlet can be connected with other gas detection devices such as a GC-MS and a liquid chromatograph, read gas compositions are compared with compositions at the gas inlet, and the result is the detection result of the indoor self-purification effect.