Abstract: The changes in the content of both substrate glucose and ammonium sulfate, pH and flocculation activity and output of compound microbial flocculant in differ ent periods of growth cycle compound bioflocculant producingbacterium were studied. In the whole growth cycle, pH was stable, the change of carbon and nitro gen source was obvious, the content of nitrogen was consistent with the source of carbon; the maximum of flocculationactivity reached to 97.35% at 60 h point after steady period, then the numerical value of flocculation activity fell down, but not obvious. Flocculation activity had a wide region of largest value and the maximum output of flocculation (3.02 g/L) was in this region. The result of cell flocculation and growth of cell got positive pertinence. Appraisal result is: 3 bacteria are respectively Brevibacterium mcbrellneri, Burkholderia glumae and Cryptococcus albidus var aerius.　The experimental result offered a foundationto further investigations of contributing factor on flocculation and mechanism.　It provided gist in theory for culture in industrial application, too.

Key words: compound microbial, flocculation productbacterium, growth cycle, change of parameter