The invention discloses a high-temperature-resistant cellulose degradation bacterium which is a streptomyces thermocarboxydus. The preservation number of the cellulose degradation bacterium is CGMCC No.12135. The bacterium is capable of producing a large quantity of enzymes at the high temperature of 40-70 DEG C; the cellulase of the bacterium is high in activity and has the characteristics of high temperature resistance and efficient degradation of cellulose; the bacterium can be used as a microbial agent, can be applied to a high-temperature composting system, and is suitable for composting the garden wastes.