The purpose of the study was to develop a flash-based animation program to prevent the relapse of illicit drug use among the adolescents who had ever used illicit drugs. We designed 13 flash animations which emphasized on life skills related to illicit-drug-use prevention, including refusal skills, stress coping, problem identifying and solving, etc. The pre-post changes of life skills and using illicit drugs were viewed as program effectiveness. A total of 29 students were recruited from eight high schools and able to complete the questionnaire at the baseline and after intervention. Of the participants, 16 students participated in the prevention program received the 12 sessions integrated with flash animations over 3 months and 13 students received a conventional illicit-drug-use prevention course. The results indicated that the scores of life skills were significantly higher in the program participated students than those of students receiving conventional course, with an apparent improvement on refusal skills. Moreover, the participants in the intervention group all passed the urine test and did not use illicit drugs after 3 months. The preliminary results revealed a preventive effect of the flash-based animation program to prevent illicit-drug-use among the adolescents who had ever used illicit drugs.