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[Objectives] A better method for evaluation of the degradation ability of rice straw-degrading bacteria was explored. [Methods] Ten strains of straw-degrading bacteria were used to study the relationship between the hydrolysis ring(on CMC-Na plate) , carboxymethyl cellulose (CMCase)and xylanase activity in rice straw powder as carbon source for liquid fermentation medium and the relative degradation rate of rice straw. [Results] The hydrolysis zone diameter on CMC-Na plate(D) , the ratio of hydrolysis zone to colony diameter( D/d) , the largest CMCase and xylanase activities of each day of strains were not significantly correlated with their relative degradation rate(RDR)on rice straw( P>0.05). Positive correlations were observed between the CMCase or xylanase activities accumulated for one week and RUR(P<0.05) , while the total cumulative enzyme(CMCase plus xylanase) activity in one week was significantly correlated with RDR (P<0.01). [ Conclusions] The cumulative enzyme activity of strain is better to evaluate the actual degradation effects, and this new evaluation method provides a more accurate identification of reference for the degradation ability of the straw-degrading bacteria. [ABSTRACT FROM AUTHOR]