The present study evaluates a specific cognitive-behavioural group intervention for pure victims of school bullying, employing a longitudinal design with mixed methods. 68 high-risk pure victims were identified from 5071 schoolchildren through screening measures and structured interviews, and assigned to 10 treatment groups. They completed a self-report questionnaire comprising measures of anxious/depressed problems and peer victimization prior and after the treatment, and at 1-year follow-up. The students, their teachers, and parents/guardians also received structural interview assessing students’ cognition, affection, and behaviour pertaining to peer victimization before and after the intervention. The results showed that the students’ physical, verbal, and total victimization, social exclusion, and depressed-anxious scores decreased from the pre-test to the one-year follow-up. They also reported a more realistic self-image, less self-blame, more positive outcome evaluation, less fearful, and employ more rational strategy when encountering problems in post-test interviews. Teachers and parents also noted the student experienced less peer victimization, had learnt to speak up against victimization and was less isolated in class. The results suggested the CBT program was effective for treating pure victims with internalizing problem.