目的　了解沂蒙山区健康青少年性发育规律 ,为制订相应的性教育计划及为临床判断性发育异常提供理论依据。方法　对 1735名沂蒙山区健康青少年身高、体重、初次遗精或月经初潮年龄及第二性征发育进行调查 ,并使用游标卡尺对 876名男性青少年进行睾丸长径及宽径、阴茎长度及直径的测量。依据性发育指数 (DI)将青春期划分为 3期。结果　青少年青春期的开始时间男性平均为 13岁 ,女性平均为 11岁 ;男性首次遗精年龄平均为 15 2 3岁 ,女性月经初潮年龄平均为 13 38岁 ;身高速度高峰 (PHV)发生年龄男性为 14岁 ,女性为 12岁 ,体重速度高峰 (PWV)则分别为 15岁和 13岁 ;有 13 96 %女性阴毛发育早于乳房发育。结论　沂蒙山区农村青少年性知识缺乏 ,有关性教育薄弱 ,性发育延迟。本调查为偏远山区性教育研究提供了重要参考数据 Objective To understand the law of sexual development of healthy adolescents in Yimeng mountainous area and to provide a theoretical basis for formulating the corresponding sexual education plan and for judging the abnormality of clinical judgment. Methods The height, weight, age at first spermatorrhea, age of first menstrual cramps and the development of second sexual characteristics of 1735 healthy adolescents in Yimeng Mountain were investigated. The length, width and penile length of testis and the diameters of testis were measured with vernier calipers on 876 male adolescents. Adolescence is divided into three phases based on Sex Development Index (DI). Results The average age of adolescent adolescence was 13 years for males and 11 years for females. The average age of first spermatorrhea in males was 15 2 3 years old. The mean age of menarche was 13 38 years old. The height-time peak (PHV) Year-old, 12-year-old female, weight-loss rate peak (PWV) were 15 years and 13 years old; 13 96% of female pubic hair earlier than breast development. Conclusion There is a lack of sexual knowledge among rural adolescents in Yimeng Mountainous Region. Sex education is weak and sexual development is delayed. This survey provides important reference data for the research on sexual education in remote mountainous areas