Plasmonic metal-semiconductor nanostructures endow them with an enormous potential application in photocatalysis, however, the uniform deposition of metal NPs as small as a few nanometers remains a challenge. Here, we demonstrate the effectiveness of two-step polymer-network gel process in the synthesis of Ag-ZnO nanocatalyst with superior photocatalytic properties. Because of uniform distributed Ag NPs, large specific surface area and abundant surface oxygen vacancies, the Ag-ZnO nanoparticles exhibit a super high photocatalytic efficiency in comparison to pure ZnO nanoparticles. The efficiency can be further improved by optimizing the external factors, such as catalyst dosage, ambient temperature and initial solution pH. Good stability and practicability indicate its potential application in environmental purification. Our work does not only provide a feasible strategy for the synthesis of high property Ag-ZnO nanophotocatalysts, but also enriches the understanding of metal-metal oxide nanostructures.