The invention provides a copper-base powder metallurgical brake pad material for a sea-base wind turbine generator system, which comprises the following components in percentage by weight: copper, FWCuZn30 brass, graphite, sea sand, silicon carbide, ferrochrome and tin. The preparation process of the brake pad material comprises the following five steps: blending materials, pressing blank, making support steel backing, pressurizing and sintering in sections, and machining for molding. In the invention, by adopting the seawater corrosion resistant brass as a material matrix and high-content nonmetal components the weight ratio of which is more than 30%, excellent corrosion resistance, high friction coefficient and high brake moment can be obtained, and the stability of friction coefficient is good; the obtained powder metallurgical brake pad material conforms to the service performance requirements for a high-speed shaft braking device of the sea-base high-power wind turbine generator system; the material has the advantages of rational component proportion, simple machining process, good corrosion resistance, high friction coefficient, good friction coefficient stability and high strength, and is suitable for industrialized production; and the copper-base powder metallurgical brake pad material can be taken as a high-speed shaft braking material for the sea-base high-power wind turbine generator system with the power of more than 3.5MW.