The optimum flocculation were screened from the different kinds of flocculations through comparison of610nm light-transmittance,the filtration rate,the removal ratio of protein and polysaccharose. Using Al2( SO4)3and poly-AlCl3 as flocculation,their effects on the extraction of the secondary metabolites from marine bacterias were investigated by HPLC( high-performance-liquid-chromatograhy). The effects of four kinds of solid-liquid separation ways on the fermentation borth of marine bacteria were compared. Results showed that the coupling method of flocculation and membrane ultrafiltration was adaptable to highly active and rapid pretreatment of different types of marine bacteria.