Abstract: Maize stover resources were abundant in China. Composting was one of the important utilization methods of maize stover, but it had problems such as a long cycle and serious loss of carbon and nitrogen nutrients. There were few studies on the use of cellulose-degrading enzyme preparation and synergetic treatment of microorganism and enzyme for the fertilizer of maize stover. In particular, the effect of co-processing on the loss of carbon and nitrogen and the conversion of nutrients was rarely reported. This study was committed to clarify the effect of cellulose-degrading microorganism, cellulose-degrading enzyme and cooperation between microorganism and enzyme in stover composting test. Three functional microorganisms Luteimonas sp. X11-1, Aspergillus flavus Z5-3, and Trichoderma longibrachiatum Z8-2 existed in the cellulose-degrading microbial inoculum. The cellulose-degrading enzyme preparation was developed by Institute of Agricultural Chemistry of Zhejiang University. Its hydroxymethyl cellulose activity was 4.21×103 U/g, the optimum temperature was 40-60℃, and the inactivation temperature was 80℃. There are four stover composting treatments, which are separately added microbial inoculant (volume fraction 15%), enzyme preparation (mass fraction 0.8%), microbial inoculant and enzyme preparation (volume fraction 15% inoculum + 0.8% mass fraction), and not adding microorganism or enzyme as a control. The stacking temperature, pH value, carbon loss, nitrogen loss, nutrient content and compost maturity were surveyed and analyzed during the composting. The results showed that addition microorganism alone and addition enzyme alone entered the high temperature 2 days earlier than the control. The synergetic treatment entered the high temperature period 3 days earlier than the control, and the maximum temperature was 0.7-1.9℃ higher than other treatments. During the composting process the pH value of each treatment increased at first and then decreased. Compared with the control, the cumulative release of CO2 and NH3 by addition microorganism alone, addition enzyme alone and synergetic treatment were showed a downward trend. The cumulative release of CO2 and NH3 of synergetic treatment was the lowest and significantly lower than other. Carbon losses of addition microorganism alone, adding enzyme alone and synergetic treatment were 18.92%-23.91% respectively, which were 37.24%-50.34% lower than that of the control; nitrogen losses were 15.51%-19.25%, which were 54.19%-63.09% lower than that of the control. Among them, the carbon and nitrogen losses of the materials processed by synergistic treatment are the lowest. It means that the synergistic treatment of microorganism and enzyme was more beneficial to the reduction of carbon and nitrogen loss. At the end of composting, the mass fractions of total phosphorus, total potassium, available phosphorus, and available potassium of microbial inoculant treatment, enzyme preparation treatment, and synergetic treatment were increased 34.48%-62.93%, 71.43%-117.14%, 10.76%-15.65%, 17.10%-23.23%, respectively, in which the nutrient conversion effect of the material by synergistic treatment was the best. Addition microorganism alone, addition enzymes alone, and synergistic treatment could shorten matured compost times which advanced 10, 16 and 18 days. The above results showed that addition of microbial inoculant alone, addition enzymes preparation alone and synergistic treatment could shorten the composting time and promote the nutrient transformation of materials. In summary, the synergistic treatment of microorganism and enzyme was beneficial to decrease the loss of carbon and nitrogen, promote nutrient transformation and shorten compost maturity time, which was the best treatment. The results can provide the theoretical basis for co-processing of microorganism and enzyme in stover composting.