Abstract: This article analyses the composting which is made up by the poultry dung and cow manure. The point is a carbon-nitrogen ratio(C/N) variation of the three kinds of composting. The composting lasted 49 days.The fermentation period of 1:0.5 poultry-cow ratio is 30 days.The result reveals that both of total carbon(TC) and total nitrogen(TN) decreased all the time,and TC was decreasing faster than TN.The carbon-nitrogen ratio decreased slowly.When the three kinds of composting finished,the best one was the poultry-cow ratio is 1:0.5.