Abstract: In this experiment,Du-Mon and Du-Han crossbreed fattening lambs were randomly selected and weighted under the same breeding condition at 90-day-old and 150-day-old from Siziwangqi of Inner Mongolia,the statistics of average body weight and daily gain of fattening lambs was made,and the fattening effect of Du-Mon and Du-Han crossbreed sheep also be discussed.The results showed that the average body weight and daily gain of Du-Mon crossbreed fattening sheep at 90-day-old and 150-day-old lambs were significantly higher than that of Du-Han crossbreed.