The purpose of this study is to provide the information for the guiding principle of Physical Education in elementary school, and the development of it, presenting the basic information about the activation of the After-School Physical Activities with providing the effect on the physical self-concept of elementary school students participating in the After-school physical activities. To achieve this purpose, 428 elementary school students of grade 5 and 6 in T-city, Gyungsangnamdo were surveyed by the physical self-concept test. The data was analyzed statistically by the frequency analysis, confirmatory factor analysis, reliability analysis, t-test, one way ANOVA using SPSS 12.0 for Windows and Amos 5.0 programs. Scheff\'s test was used after the fact and the result are as follows. 1. The difference of physical self-concept according to general characteristics First, concerning the elementary school students\' physical self-concept according to gender differences, the boys had higher perception of physical self-concept(p<.01), which was shown by the statistically significant difference in appearance, health, regular exercise, lean body, athleticism, and endurance. Second, concerning their physical self-concept according to BMI(Body Mass Index), the underweight among them had the highest perception of physical self-concept(p<.01), which was shown by the statistically significant difference in flexibility, lean body, muscular strength, athleticism, and endurance. Third, concerning their physical self-concept according to the different grades, the 5th graders had high perception of physical self-concept(p<.05), which was shown by the statistically significant difference in the flexibility. 2. The difference of physical self-concept according to participation in the After-School Physical Activities First, between participants and non-participants, the participants in physical activities showed a very high perception of the physical self-concept(p<.001). Second, according to the period of participation, the students participating for more than 2 years showed the highest perception of the physical self-concept( p<.05). Third, according to the activities that they attended, those who participated in soccer had the highest perception of the physical self-concept(p<.05). Fourth, according to the frequency of participation, those who participated 2 or 3 times a week had the highest perception of the physical self-concept(p<.01).