Abstract: Straw, as the main byproduct of crops, is an important kind of renewable resource. There are a large number of microorganisms that can degrade straw, therefore, bioconversion of straw into available animals feed using the microorganisms has great significance for solving the contradiction about man and livestock's fight for grain. Firstly, the structure characteristics of straw and the disadvantages of straw feed were analyzed. Secondly, the species of microorganisms used in straw degradation and their roles in the process were detailed, then the choice of microorganisms and the features of different fermentation methods were compared. Finally, the problems during the biodegradation and the direction to solve them were expounded, to provide a theoretical reference for exploitation and utilization of straw.