In order to study the rate of occurrence and the present health situation of obese middle school students in Hunan province，15, 600 students from 20 middle schools in Hunan province were selected randomly as study object，among them 7, 560 (48 %) were junior middle school students (3, 400 males and 4, 160 females) and 8, 040 (52 %) were senior middle school students. Results showed that the detected obese number (For female：BMI＞25，PBF＞25 %；Male：BMI＞25，PBF＞20 % ) were 1, 263 which constituted a proportion of 8.1 %. They were also compared with normal weight students in body shape，cardiopulmonary function and related index of fitness. The findings showed significant difference. Draws conclusions as the following, the rate of occurrence for obese students is higher in Hunan province, the level of heart and lungs are worse ；the PBF percentage is high and the fitness is decreasing. Strongly suggests that our society pays more attention to the obesity problems of middle school students and takes timely corrective and preventive action on their obesity occurrence.