The ZnO particles with mesoporous and lamellar structure were synthesized in the method of precipitation, using zinc acetate as precursor. The ZnO particles were characterized by the means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 adsorption–desorption measurements. The photoactivity of as-prepared ZnO particles was evaluated by degradation experiment of methyl orange aqueous solution. The results showed the obtained ZnO particles were irregular polygons with lamellar structure, and the particle size was in the range of 50 nm to 300 nm. According to XRD and N2 absorption results, ZnO particles were pure and integrated crystals with high crystallinity, and adsorption-desorption isotherms correspond to the typical type IV isotherm with a hysteresis loop of type H3, which showed ZnO particles had mesoporous structure with slit pore shape. The ZnO particles had high photocatalytic activity, the maximum degradation rate of methyl orange aqueous solution can reach 99%. When reused for the fifth time, the photocatalytic activity of ZnO particles was similar with the fresh ones, and recycled for the tenth time, the degradation rate of methyl orange aqueous solution still standed by 84.7%.