The invention provides a Cu-Cu2O-CuO ternary copper catalyst and a preparation method and application thereof. The Cu-Cu2O-CuO ternary copper catalyst comprises, by mass, 1%-40% of Cu, 30%-80% of Cu2O and 10%-40% of CuO, wherein the sum of the mass percentages is 100%. The Cu-Cu2O-CuO ternary copper catalyst is uniform in component, adjustable in content, small in particle size and narrow in particle size distribution range; since the ternary copper catalyst can be prepared by simple comproportionation, simple preparation process, convenience in operation, low cost, freeness of environment pollution and suitableness for industrial production are realized. The ternary copper catalyst is used for 'direct method' based organosilicon monomer synthesis, and selectivity of dimethyldichlorosilane which is a target product can be remarkably improved while conversion rate of silicon powder can be greatly increased.