This study was designed to develop an effective smoking cessation program on Internet, and to determent the efficacy of a health educational intervention. A four-week campaign was developed for junior high school students as the educational program. The author used the nonequivalent pretest-posttest control group design to explore the effect of the education program. The subjects were selected from two junior high schools in Taipei city, Young-Jyi and Syajh. The treatment group is from Young-Jyi junior high school, which has received four-week educational intervention program. The control group is from Syajh junior high school, which didn’t receive any treatment. The instruments included pretest and posttest self-report structured questionnaires. There were 416 valid respondents (196students of the treatment group and 220 student of the control group). This study has found significant results regarding the efficacy of the educational program. The mean scores of knowledge, attitude, self-efficacy and behavior about smoking cessation in the post-test were significantly higher than the scores in the pre-test within the treatment group. In the posttest, the mean scores of knowledge, attitude and self-efficacy about smoking cessation in the treatment group were significantly higher than the scores in the control group. However, the Internet educational program did not significantly influence students’ smoking cessation behavior. In conclusion, the Internet educational program is an effective tool. I suggest that health educators can work together with computer engineers and cartoonists to create effective and interesting smoking cessation programs in the future. Besides, the using of the transtheoretical model, health communication theory and social cognitive theory in planning interactive smoking cessation programs will trigger off students’ learning motivations.