Flocculation was a common method of wastewater treatment. Introducing magnetic particles into flocculant could improve the performance of wastewater treatment and the separation efficiency of sediment. The inorganic polymer magnetic polysilicate aluminum zinc-chitosan (Fe3O4-PSAZn-CTS) composite flocculant was prepared with Fe3O4 nanoparticles, sodium silicate, aluminum sulfate, zinc sulfate and chitosan as raw materials. It was applied to the simulated water sample prepared from kaolin. The pH, the dosage of Fe3O4, the molar ratio of aluminum and zinc to silicon, the molar ratio of aluminum to zinc, and the mass ratio of aluminum and zinc to chitosan were optimized by single factor test, and the optimal preparation conditions of Fe3O4-PSAZn-CTS flocculant were determined. Through FTIR, XRD, TGA and SEM analysis of Fe3O4-PSAZn-CTS, it was proved that Fe3O4-PSAZn-CTS was a new magnetic composite polymer with amorphous surface by Fe3O4 and PSAZn-CTS closely bonded. Then, the dosage of flocculant, the pH of simulated water sample, the sedimentation time after flocculation were optimized by single factor experiment, and the optimal flocculation conditions of Fe3O4-PSAZn-CTS were obtained. Finally, the raw water sample of Songhua River in Jilin section was treated under the optimal conditions, and the flocculants were separated and dried. The magnetic floc reuse experiment was conducted by adding 50% dried flocculant and 50% optimal dosage of initial flocculant, and the turbidity removal rate could still reach more than 95%.