Different extra carbon sources(glucose, sucrose and straw powder）were added during sewage sludge composting. According to the results, separate add of the glucose(2.46 g/kg·ds）and sucrose(2.17 g/kg·ds）could reduce NH3 emission compared with the amount of NH3 emission(3.05 g/kg·ds). No significant reduction of nitrogen loss was found in the mixture of P3 amended with straw powder alone(3.1 g/kg·ds). Adding the mixture of sucrose and straw powder had significant effect on reducing ammonia emission(1.92 g/kg·ds). A good linear correlation between the carbon degradation rate and ammonia emission was found with correlation coefficients of -0.94(p<0.005). The combination of straw with glucose and sucrose could enhance the decomposition of organic carbon. The carbon source which has more readily degradable composition is helpful to nitrogen immobilization.