The utility model discloses a variable operating platform for a fabricated building staircase. Relating to the field of simple operating platforms, the utility model discloses a variable operation platform for a fabricated building staircase. The device comprises a square ring and a steel wire mesh pedal, the surface of the steel wire mesh pedal is fixedly connected with the inner wall of the square ring; cylindrical pins are fixedly connected to the front face and the back face of the square ring. The surface of the cylindrical pin is movably sleeved with a square rod; a through groove is formed in the left side of the square rod, the surface of a fixed shaft fixedly connected with the inner wall of the through groove is movably sleeved with a movable rod, sliding grooves are formed in the front face and the back face of the square ring and located in the left side of the cylindrical pin, the inner wall of each sliding groove is movably connected with the surface of a round rod, and the end, away from the steel wire mesh pedal, of the round rod is fixedly connected. Through the arrangement of the square rods, the movable rods, the round rods, the bolts and the guardrails, the problem that at present, when the strength of a cast-in-place concrete stair beam does not meet the installation requirement, a prefabricated stair cannot be installed, and construction and passing of constructors are inconvenient is solved.