The main objective of this work is to synthesize high surface area zinc oxide/ silica composite nanoparticles via a facile and systematic process. Regarding the importance of surface area in application of such nanoparticles, variation of this factor was studied by change of reaction parameters including concentration of zinc acetate solution, pH, and calcination temperature via Response Surface Method combined with Central Composite Design (RSM-CCD). Optimum conditions were obtained as a concentration of 0.013 mol -L-1, pH of similar to 8.97, and calcination temperature of 541.6 degrees C. Optimum nanoparticles were characterized by various analyzes such as XRD, BET, AAS, FTIR, TGA/ DTA, FESEM, EDS, and TEM. Comparison of two 0.1 g/g (10 wt %) ZnO/Silica samples with the optimum (337 m(2) . g(-1)) and non-optimum (95 m(2). g(-1)) surface areas indicated that nanoparticles prepared at the optimum conditions with average diameter of about 18 nm showed a H2S adsorption capacity of about 13 mg per gram of sorbent. This value was higher than that of the non-optimized sample (6 mg per each gram of sorbent).