NOVELTY - Producing microbial flocculating agent using bagasse, comprises: (a) preparing a culture medium; (b) adding the culture medium into a fermenting tank, adopting the high pressure steam heating process, stirring and cooling the fermentation tank, adding fresh Trichoderma spore liquid and culturing; (c) sterilizing and then cooling the fermenting liquid, inoculating microbial flocculating agent-producing strain and fermenting, collecting the culture solution, filtering with a gauze to remove the strain and obtain the fermentation liquid with flocculation activity.    USE - The method is useful for producing microbial flocculating agent using bagasse.    ADVANTAGE - The method: is economical; utilizes bagasse as the sole carbon source of the culture medium, and utilizes the high-yield cellulase-producing strain and the microbial flocculating agent-producing strain in the fermenting process to achieve high yield of cellulase and microbial flocculating agent, which are biodegradable and environment friendly and expands the resource utilization of the bagasse; avoids the cellulase purification process and utilizes the residual substrate for producing flocculating agent after Trichoderma fermentation; improves the utilization rate of the raw material and reduces the waste water discharge, does not produce secondary pollution, and adopts simple and easily controllable fermentation process, hence it is suitable for mass production.    DETAILED DESCRIPTION - Producing microbial flocculating agent using bagasse, comprises: (a) preparing a culture medium containing (in g/l) carbon source (10-50), nitrogen source (1-5), potassium dihydrogen phosphate (1-5), magnesium sulfate (0.1-0.5), and the water (balance amount), where the carbon source is bagasse; (b) adding the prepared culture medium into a fermenting tank, adopting the high pressure steam heating process so that the tank pressure is maintained at 0.1-0.11 MPa to sterilize, stirring and cooling the fermentation tank with cooling water to attain the fermentation temperature of 23-35 degrees C, adjusting the stirring speed rate as 100-300 revolutions/minute, maintaining the air flow rate as 80-50 ml/minute and the tank pressure as 0.015-0.025 MPa, adding fresh Trichoderma spore liquid accounting for 1-5% of the culture medium volume, where spore liquid absorbance (A) is 0.6, and culturing for 24-48 hours; (c) adjusting the fermenting liquid to pH value of 4-6, sterilizing and then cooling to room temperature, regulating the stirring speed rate at 100-300 revolutions/minute, maintaining the air flow rate at 80-150 ml/minute and the tank pressure at 0.015-0.025 MPa, inoculating microbial flocculating agent-producing strain with an inoculating amount of 0.05-0.25 g/l and fermenting at 25-37 degrees C for 36-72 hours, collecting the culture solution, and filtering with a gauze to remove the strain and obtain the fermentation liquid with flocculation activity.