The invention discloses an autoclaved aerated concrete block demoulding device. The device comprises a base. Lifters are arranged on the two sides of the top of the base correspondingly, and the output ends of the lifters are connected with supporting rods correspondingly. First rotary motors are fixed to one sides of the top ends of the supporting rods correspondingly, the output ends of the first rotary motors are connected with crankshaft turning discs correspondingly, and connecting columns are arranged at the tops of one sides of the crankshaft turning discs correspondingly. Connecting plates are arranged at the tail ends of the connecting columns correspondingly. According to the autoclaved aerated concrete block demoulding device, second baffles and first baffles move relatively through arranged electric telescopic rods, and the purpose that the first baffles and the second baffles are separated is achieved; and the arranged first rotary motors rotate to drive the crankshaft turning discs to rotate, the crankshaft turning discs drive the connecting plates to make circular motion through the connecting columns, accordingly, the first baffles, the second baffles and a bottom plate are driven to make circular motion, during moving, a block swings and is separated from a mould more easily, the two modes are combined, the demoulding effect is good, and demoulding is faster.