Abstract: Objective To investigate the nutrition status and its influencing factors among children under three years old in rural area of Tibet,so as to provide reasonable suggestions for policy making.Methods The proportion population sampling(PPS)method was used to investigate1 513 children under three years old in 72 townships of 6 regions.HAZ,WAZ and WHZ were used as nutritional indexes.Results The prevalence of stunting(height for age Z-score < -2),underweight (weight for age Z-score < -2)and wasting(weight for height Z-score < -2)was 33.9%,16.5% and 3.4%,respectively.Different gender and regions had different prevalence of malnutrition,and the stunting and underweight prevalence in the area of 4 500 meters above the sea level were 36.5% and 19.1%,respectively.The under weight prevalence rate in boys was much higher than that of in girls(P<0.01).Conclusion Malnutrition is prevalent among children in Tibet.The intervention should be done according to the influence factors.