Embodiments of the present invention provide a liquid crystal lens, a manufacturing method thereof, a manufacturing apparatus and a 3D display device. The manufacturing method of a liquid crystal lens, comprising: obtaining an actual effective refractive index profile of a liquid crystal layer by simulating, and the liquid crystal layer having an initial pretilt angle; determining a difference region in which a difference exists between a predefined standard pretilt angle and the initial pretilt angle of liquid crystal in the liquid crystal layer and a non-difference region, according to standard and actual effective refractive index profiles; simulating an orientation of the liquid crystal in the difference region of the liquid crystal lens, and determining the standard pretilt angle of the liquid crystal in the difference region; and irradiating the liquid crystal in the liquid crystal lens for alignment.