The utility model provides a cast-in-place concrete pile top elevation control device, which belongs to the technical field of constructional engineering and comprises a support, a tension sensing switch, a winder, a winding motor, a first fixed pulley, a second fixed pulley, a traction rope with scales, an alarm device and a buoyancy detection hammer. The support comprises a support body and a transverse cantilever. The tension sensing switch is arranged on the frame body, and the end part of the tension sensing switch faces downwards and is provided with a first fixed pulley; the second fixed slide is mounted at the end, extending out of the frame body, of the transverse cantilever; the traction rope is wound on the winder, is led out from the winder, sequentially penetrates through thefirst fixed pulley and the second fixed pulley and then is connected with the buoyancy detection hammer; the buoyancy detection hammer is hollow, so that high-density substances can be added and reduced to control the quality, and the use in different construction sites is realized; the device can effectively identify the interface of the concrete layer and the laitance layer, avoids errors causedby traditional manual measurement, and improves the control precision of the cast-in-place concrete pile.