Abstract: The study determined the change condition of major nutrients in sorghum straw、 corn straw、 soybean straw and sweet potato vine in different conservation methods(open-air conservation 、shed conservation 、silage and ammoniation). And two steers (450±15kg) with permanent rumen cannulas were used to determine the effects of conversation methods on the rumen degradabilities of DM、OM、NDF and ADF.The results show: The CP content of straws was higher significantly affected by the conservation methods(P<0.01); The conservation methods higher significantly affected the OM content of sorghum straw (P<0.01) and significantly affected of sweet potato vine (P<0.05); higher significantly the NDF content except sweet potato vine (P<0.01), significantly the ADF content of sorghum straw and corn straw (P<0.05). higher significantly of soybean straw and sweet potato vine; The WSC content of straws was higher significantly affected by the different conservation methods (P<0.01). The oven-drying and ammoniation improved the rumen degradabilities of DM、OM、NDF and ADF of straw except soybean straw.