Objective To find out a relatively accurate teenagers' age estimation method.Method 233 cases were collected with emphasis to their type of crime, the intervals from commitment of the crime to age assessment, and the differences between self - reported and appraised age. By regression equation (method 1), CHN evaluation (method 2) and comprehensive method designed by the authors (method 3), 130 male teenagers whose osteophiph-ysis hadn' t been closed were compared and analyzed, statistically andyzed by Chi square test. Results The analysis showed : (1) 72.10% cases were of plundering and robbing type. (2) The intervals from commitment of the crime to age assessment in 75.10% cases were less than six months. (3) Self- reported ages in 60.73% cases were less than appraised age. (4) The accordance rate between method 1, method 2 to method 3 was 90.77% and 83.08% respectively. Conclusion The age estimation on living body should be performed as soon as possible after commitment of the case, and method 1 seems to be more accurate than method 2 in estimating 18 years-old person,and the method designed by us should be better than the other two.