Abstract: Tadpoles of Rana catesbeiana and R.chaochiaoensis were collected from the same pond in the northeast suburb of Kunming.Their foods were analyzed.The results showed that food items of R.catesbeiana were eight types and 51 categories in tadpole stage Ⅰ,and eight types and 33 categories in tadpole stage Ⅱ.Food items of R.chaochiaoensis were six types and 30 categories in tadpole stage Ⅱ.Bacillariophyta,Chlorophyta,Cyanophyta were main items of food components in two species.However,there was a remarkable difference of food categories between tadpole stage Ⅱ of R.chaochiaoensis and stage Ⅰ of R.catesbeiana,and there was not difference of food categories between tadpole stage Ⅱ of R.chaochiaoensis and R.catesbeiana.Comparisons among tadpole stage Ⅱ of R.chaochiaoensis with stage Ⅰ and Ⅱ of R.catesbeiana,food niche overlap indexes were 0.6952 and 0.6887;biomass of unit body weight (food biomass/average weight) were 10.96 times and 15.48 times of two stages of R.catesbeiana;the indexes of percentage similarity of food (PS) were not high,I.e.54.95% and 58.11%.Comparisons between the same body weight tadpoles of R.chaochiaoensis and R.catesbeiana,the tadpole of R.chaochiaoensis has greater food quantity.The biomass needed for survival by the tadpole of R.chaochiaoensis was higher than the tadpole of R.catesbeiana.The results both in this text and observed in the field indicated that there was a drastic competition between tadpoles of R.catesbeiana and R.chaochiaoensis in food.Tadpoles of R.chaochiaoensis were in a disadvantageous position.