Purpose: This study was aimed to develop a WBI(Web Based Instruction) program on safety for 6th grades of elementary school students and to test the effects of it. Method: The web site is http://www.safeschool.co.kr. The effect of it was tested from Mar 24, to Apr 30, 2003. The subjects were 150 students. Data were analyzed with descriptive statistics, and $x^2$ test, t-test, and repeated measure ANOVA. Result: In the knowledge of the safety precaution, the preliminary test was mean 17.8, immediate post-test was mean 20.9 and 4 weeks post-test was mean 20.9, there were significant differences statistically among three points of time. In the attitude of the safety precaution, the preliminary test was mean 75.1, the immediate post-test was mean 80.8 and 4 weeks post-test was mean 80.4, which showed significant difference statistically among three points of time. For the motive of learning to the safety precaution, it was significantly higher statistically in the WBI. As a result, the WBI group had totally longer effects on knowledge, attitude and motivation of the safety accident prevention than the textbook-based instruction. Conclusion: WBI program be used in each class to provide more effective safety instruction.