The invention provides an MOCVD preparation method for a silicon-based quantum dot laser material. The MOCVD preparation method sequentially comprises the following steps that a low-temperature GaAs nucleating layer is made on a clean monocrystalline silicon substrate; a high-temperature GaAs buffering layer is made on the low-temperature GaAs nucleating layer; a strain superlattice structure is made on the high-temperature GaAs buffering layer; an n-type ohmic contact layer is made on the strained superlattice structure; an n-type limiting layer is made on the n-type ohmic contact layer; a lower waveguide layer is made on the n-type limiting layer; a multi-layer quantum dot active area is made on the lower waveguide layer; an upper waveguide layer is made on the multi-layer quantum dot active area; a p-type limiting layer is made on the upper waveguide layer; and a p-type ohmic contact layer is made on the p-type limiting layer. By the adoption of the MOCVD preparation method, material growth and preparation can be evenly and rapidly completed on a large area in a high repetitiveness manner, and cost is lower. The MOCVD preparation method is more suitable for the industrialization demand.