The multiple quantum well structure for 850nm vertical cavity surface emitting laser device based on GaAs/AlxGa1－xAs has been design in this paper. The major process parameters of Low Press-Metal Organic Chemical Vapor Deposition (LP-MOCVD), such as the growth temperature, the reaction chamber pressure, total carrier gas flow rate and so on, have been optimized and the growth of complete epitaxial structure has been carried out. The experimental results showed that components of the GaAs/AlxGa1－xAs multiple quantum well structure devices was obtained under the condition of 700℃, the best composition x is 0.24 by the Photoluminescence (PL) spectrum comparison test and a good surface morphology of the multiple quantum well structure had been obtained. The optimum growth rategrowth rate was 0.34~0.511 nm/s ultimately.