The invention discloses a method for preparing rice bran bioactive peptide through solid-state fermentation of mixed bacteria species. The method comprises the steps: performing solid-state fermentation and culture of rice bran by using mixed bacteria species of aspergillus niger AS3.410, AS3.350 and AS3.365, and aspergillus oryzae AS3.910, firstly, activating bevel bacteria species to generate a seed culture medium, then performing the combined inoculation of four hypha in the sterilized rice bran, performing solid-state culture, and then separating and drying to obtain the mixed rice bran. According to the invention, composite microorganism microbial populations, such as high-yield cellulase, starch enzymes, pectinase, glucamylase, fat enzymes and protease are selected and used, and the rice bran is directly fermented by a solid-state fermentation method, not only is the nutritional level of leavening improved, but also some bitter peptide groups are modified and reorganized, so that the peptide of the made rice bran has no bitterness or abnormal taste basically, the production technology is simplified, the production cost can be effectively reduced, pollution is avoided, and the method is suitable for the large scale industry production of the rice bran bioactive peptide.