From 2013 to 2014,40 Rattus niviventer confucianus,19 Meriones meridianus (Pallas) ,43 Apodemus peninsulae and 46 Spermophilus alashanicus were caught by the day trapping method on the west mountainside of the Helan Mountains.One way analysis of covariance was applied to analyze the length,fresh weights (including the content) and net fresh weights (excluding the content) of digestive organs.LSD (least significance difference) was then used to perform multiple comparisons.The results show that there are highly significant interspecific differences (p<0.01) between general length,total fresh weight and total net fresh weight of digestive organs of the four rodents.In regard to the changes in organs,the length of organs,the fresh weight and the net fresh weight of S.alashanicus (the dominant species of the Helan Mountains) are significantly longer or heavier (P<0.05) than those of the other three species; the length of digestive organs of R.niviventer confucianus are longer or heavier than those of A.peninsulae.Both of these species live in the bushwood and the forest edge.This phenomenon indicates that it is easier for R.niviventer confucianus to get food in food competition.The four rodent species have changed their digestive tract morphology in order to adapt their feeding habits.