Background: Concealed penis is an anomaly in infants and adolescents, accurate diagnosis of different types of which requires extensive experience. In general, an experienced physician can diagnose the type of abnormal penis by careful observation and then provide the corresponding treatment. The appearance of trapped penis and webbed penis is easier to distinguish than that of other abnormal penises. However, congenital concealed penis is easily confused with phimosis and obesity concealed penis, and it is not easy to distinguish clinically, especially for inexperienced physician. Objectives: This study aims to provide an auxiliary measurement method to assist diagnosis of concealed penis types. Methods: This study enrolled 105 children diagnosed as phimosis, 88 as congenital concealed penis, and 78 as obesity concealed penis. Multifunctional protractor was used to measure the foreskin angle and penis-scrotum angle. The foreskin angle was defined as the angle between the ventral and dorsal sides of the penis body and the line extending to the foreskin, which was the sagittal position of the natural state of the penis when the child lies down. The penis-scrotum angle was defined as the angle between the ventral side of penis and the scrotum. All measured data were recorded by professional physicians, and the differences between different groups were compared using t-test. Results: The average foreskin angle in the phimosis, congenital concealed penis, and obesity concealed penis groups were 10.05°, 74.34°, and 8.86°, respectively. The average penis-scrotum angle in the three groups were 6.98°, 118.65°, and 85.59°, respectively. Annular wrinkle numbers in the three groups were 0.26, 0.32, and 2.68, respectively. The difference of the groups was statistically significant (P < 0.05). These results indicated that congenital concealed penis had greater foreskin and penis-scrotum angle. Obesity concealed penis had moderately large penis-scrotum angle and higher number of annular wrinkles. On contrary, the three indicators in phimosis were the lowest. Conclusions: This evaluation system can provide an auxiliary way to help the diagnosis of different types of concealed penis in children and provide a basis for subsequent treatment. In addition, Experienced physicians teaching new physicians/students, can also use this as an auxiliary explanation.