The invention provides a thickness controllable method for preparing a semiconductor material on insulator. The method comprises: 1) carrying out epitaxy on a doped monocrystal thin film on the surface of a first substrate; 2) carrying out epitaxy on a heavily doped single crystalline layer and a top layer semiconductor material in sequence; 3) injecting stripped ions to the preset depth positions of the first substrate under the monocrystal thin film; 4) providing a second substrate with an insulating layer, and bonding the insulating layer and the top layer semiconductor material; 5) making the heavily doped single crystalline layer and the first substrate separate from the monocrystal thin film; 6) and using a preset solution to etch to remove the heavily doped single crystalline layer, wherein the etching speed of the heavily doped single crystalline layer by the preset solution is larger than the etching speed on the top layer semiconductor material by the heavily doped single crystalline layer. The method realizes stripping through the doped ultrathin monocrystal thin film, and a peeling surface is controlled in a very thin layer. Through a high selection ratio etching process, a semiconductor material on insulator which is high in quality and high in thickness controllability can be manufactured.