Organic silicon monomer is the pillar of organic silicon industry,which is directly synthesized by Rochow reaction. A fluidized bed membrane reactor was applied to investigate effects of CuCl morphology,reaction temperature,particle size and gas velocity on the Rochow reaction. Results indicated that CuCl morphology had less effects on the Rochow reaction. The dimethyldichlorosilane ( DMDC ) selectivity increased with the decrease of reaction temperature,and the optimized reaction temperature was 300 ℃ and the DMDC selectivity could be promoted to 90％. The amount of CuCl carried out with gas from the fluidized bed decreased with the decrease of Si particle size when the gas velocity was at 1. 1 Umf,dmm/s (Umf,d is the minimum fluidized velocity of Si particle whose size is d μm),but both the DMDC selectivity and Si conversion sharply decreased. Both the decrease of Si particle size at the same gas velocity and the increase of gas velocity at the same Si particle size would lead to the decrease of Si conversion . The DMDC selectivity was 90％ when the gas velocity was 15. 6 mm/s and Si particle size was 200 μm.