Cavity forming die, using method and self-checking method

The invention relates to the technical field of fabricated concrete, in particular to a cavity forming mold, a using method and a self-checking method. The cavity forming mold comprises an inner mold, the inner mold comprises a base and lifting assemblies arranged on the base in rows, each lifting assembly comprises a fixing part and a top support, the inner mold further comprises a first magnetic part and a second magnetic part, the first magnetic parts and the second magnetic parts are arranged on the fixing parts and the top supports respectively, and the first magnetic parts and/or the second magnetic parts have/has variable magnetism; the top support is arranged on the fixed part in a lifting manner through variable magnetism; and the outer cover covers the periphery of the inner mold and is suitable for isolating concrete. According to the cavity forming mold, forming of a prefabricated part cavity is achieved through lifting of the jacking support on the fixing part, operation is easy, demolding is con