The invention discloses a method for enhancing a nickel-phosphorus composite deposit by using modified nano silicon dioxide particles. The method is characterized by using the nano silicon dioxide particles after surface chemical nickel plating as enhancement bodies, designing and optimizing a process and a formula to prepare a novel nickel-phosphorus chemical composite deposit, reducing the agglomeration of nano particles, and improving the degree of scatter and the deposit rate of the particles in the composite deposit, and the hardness and the abrasion resistance of the composite deposit. The method belongs to the field of surface technology and material preparation, the result of the method can be widely applied in a plurality of fields such as mechanics, electronic industry, automobile industry, petrochemical industry, civilian use and the like. By using the method, the requirements on raw materials and production equipment are low, the process has strong controllability, and an obtained product of the composite deposit is uniform and has high hardness, abrasion resistance and high temperature resistance.