Abstract: Based on response surface methodology，a self-developed cage gas absorption device was constructed to simulate emission characteristics of ammonia and hydrogen sulfide in enclosed large-scale farms.Taking pH value of phosphoric acid absorption solution and concentration of sodium carbonate modified activated carbon impregnation solution as design factors，relevant mathematical model was established，and response surface model was obtained to obtain optimal process parameters.Results showed that absorption rate of ammonia and hydrogen sulfide was affected by concentration of activated carbon impregnation solution more than by change of pH value of phosphoric acid.Mathematical model and response surface of ammonia absorption rate and hydrogen sulfide absorption rate were reasonable（correlation coefficient was 0.9910 and 0.987 1 respectively）.Optimum process parameters were as follows：pH value of phosphoric acid absorption solution was 5.25，concentration of impregnation solution of activated carbon modified by sodium carbonate was 6.3%.Under this condition，absorption rate of ammonia gas was 98.978%（relative error was 0.005%），hydrogen sulfide absorption rate was 90.837%（relative error was 0.006%）.