The authors of this study adopted an approach from cognitive behavior modification to design a SMART strategy, and applied the intervention to high school students. This study used a multiple baseline across-subject design to measure the degree of social anxiety among three high school students for the duration of 3 to 5 weeks, and then used the SMART strategy to intervene and document their mastering of strategies and changes of social anxiety for 15 weeks. Their anxiety level was measured and recorded 4 weeks after the intervention. The results showed that: 1) the SMART strategy can be effectively applied to high school students to address their social anxiety; 2) after the SMART strategy intervention, the students' social anxiety reduced instantly and significantly; 3) four weeks after the SMART strategy intervention, the intervention effect remained.