Actions in reducing excessive sun exposure during childhood and adolescence has been a goal of a series of programs. The objective of this study was to evaluate a multi-component high school-based intervention program to increase sun safety knowledge and sun protection behaviors among students in Beijing, China. Volunteers from three high schools in Beijing were randomized to three groups. Group A was given a 2-year intervention program consisting of multi-unit presentations plus a series of educational materials. Group B was given a 1-year intervention program with educational materials only. Group C was served as a control group. Questionnaires were answered by the three groups at baseline, year 1, and year 2. In our study, group A achieved significant improvements in all six questions about the sun and sunscreen knowledge at year 1. Group B achieved significant improvements in two questions. Both groups A and B achieved significant improvements in avoiding sun exposure at noon and seeking shade. Group A achieved improvements in almost all sun knowledge and sun protection behaviors, with the exception of using sunglasses, at year 2 compared with year 1. We conclude that school-based sun protection intervention increases student knowledge and changes student sun protection behaviors. The 2-year program could achieved better results than the 1-year program.