The purposes of this study are to present the problem of selective examination and the plan of improving them, and develop the instrument of selecting students as one of the most important factors which decide the success of education for the gifted of science at this time after 10 years` passage since this school was founded. The researcher verified the degree of predictive validity by adopting the selective examination and scientific aptitude test for new students as predictive variables and the scholastic examination and term-end examination during their school days as standard variables. The results of this study are summarized as follows: 1. It was shown that the prediction degree was higher in considering the results of selective examination and scientific aptitude test at the same time than in adopting the selective examination and scientific aptitude test respectively as predictive variables. From the results of this study, it was also found that the current entrance examination of science high school which resorted to only the selective examination to select students and imposed scientific aptitude test only to there was not suitable to selecting the students of high creativity and scientific talents. 2. It is suggested that the degree of validity and confidence should be made higher and that the standardizing of examination paper should be completed to select the gifted of science properly.