Abstract: In order to make full use of low-grade phosphate tailings powder, soy sauce slag and rice straw to achievesecondary use, these three kind of wasted resources were combined to study on the solid-state fermentation of producing phosphorus-containing organic fertilizer. During the research, the crumbly rice straw was beneficial to the air permeability of medium, the crude protein of the soy sauce slag could provide nitrogen source for the microorganism and the composite microbial agents contains Aspergillus niger, lactic acid bacteria, acetic acid bacteria and Bacillus megaterium. The result showed that the amount of tailings powder, ratio of water and fermentation time affected the complex microbial solubilizing significantly after single factor experiment and response surface analysis. Meanwhile, the optimum conditions for composite microbial agent solubilizing phosphate rock were that tailings powder: rice straw: soy sauce residue was 4.6:5:4, material to water ratio was 1:2.56, fermentation temperature was 30℃and fermentation time was 121.2 h. In these conditions, the available phosphorus content was 2 500.03 mg/kg, which provided technical support for the production of phosphoruscontaining organic fertilizer.