To solve the problem that the biological phosphorus removal be aggravated by the high-concentration phosphorus-containing wastewater (1000 mg/L) in seafood processing, the high-concentration phosphorus-containing wastewater was treated by chemical flocculation method, and the phosphorus removal efficiency of several single and mixed flocculants were analyzed. The results showed that the mixed flocculant, which prepared by polyaluminium chloride and sepiolite with mass ratio mpolyaluminum chloride∶msepiolite= 10∶3，had the highest phosphorus removal rate of 99.68% at a dose of 26 g/L, rapid agitation (160 r/min) for 60 min, and slow agitation (80 r/min) for 30 min. The XRD analysis of the precipitated flocculation agent after flocculation showed that the main component of the precipitate was CaAl3(PO3OH)SiO3, indicating that the CaO and SiO2 components contained in the sepiolite have positive effects on the removal of phosphorus.