A plant-scale composting experiment was set up，in which swine manure biogas residue and sawdust were used as raw and supplementary materials and mixed to primary C/N of 13，17，21 and 25 (B1，B2，B3 and B4) . As to the four treatments，changes of temperature，moisture，organic carbon and total nitrogen contents，and the ratio of carbon to nitrogen(C/N)during composting were monitored，differences in properties of compost products were compared，and effects of compost products on seed germination and seedling growth of rice were studied. The result showed that treatment B1 was the last to enter thermophilic phase，while B4 was the first to enter cooling phase. The duration of thermophilic phase of the four treatments were 24，36，27 and 24 d，respectively. The water contents of treatments B1and B2 were relatively high during the whole composting. Organic carbon contents and C/N of all treatments showed trend of decreasing，while total nitrogen contents increased in the early stage and decreased to some extent in the middle and late stage of composting. Organic matter content，EC and ammonium nitrogen content of the composing products increased with increasing C/N，but it appeared the opposite change for contents of nitrogen，phosphorus and potassium and pH. The composing products of all the treatments except for B1 met the national standard in contents of organic matter and total nutrients and pH. A germination test of rice seed was conducted using the composing products. The result showed that seed vigor index，shoot length，shoot fresh weight，total fresh weight，shoot dry weight and total dry weight of B3 were all the highest among all the treatments，which were 77.3%，70.7%，125.1%，44.9%，115.3% and 15.3% higher than those of deionized water control. Based on comprehensive consideration of composting process，and quality and growth promoting effect of composting products，the initial C/N value of 21 was suitable for composting with swine manure biogas residue and sawdust in production of organic fertilizer.