Background: Both Scoliosis Research Society-22 questionnaire and Spinal Appearance Questionnaire (SAQ) are well-established disease-specific patient-reported outcome questionnaires on adolescent idiopathic scoliosis (AIS). Our severe AIS patients were administered both questionnaires before and after surgery. The use of SRS-22 on surgical cases was well documented, however, SAQ which focused on patients' perceptions of spinal appearance, was merely reported. This study summarized the longitudinal changes of SAQ and SRS-22 domain scores in surgical AIS patients from preoperative to 2 years after surgery. Materials and methods: All surgical AIS patients operated on in the year 2014 to 2016 were recruited. They completed both questionnaires at (1) before surgery ("Pre-op"), (2) immediately before hospital discharge ("Post-op"), (3) 1 year after surgery ("Post-op 1 year"), and (4) 2 years after surgery ("Post-op 2 years"). Results: There were 135 severe AIS patients recruited in this study, of which 74.1% were females, and the mean age at operation was 15.97. All SAQ domains were increasing (improving) until 2 years after surgery. Curve and prominence scored the highest among the nine domains across four time points. Significant increases were observed in "Trunk shift", "Shoulders", "Prominence", "Curve", and "General". Conclusion: Improvements in appearance after surgery responded differently from function, pain, and other factors immediately after surgery. Patients' appearance perception was continuously improving after surgery despite function, pain, and mental were dropped then recovered in the next 2 years. Using SAQ in conjunction with SRS-22 in health-related quality of life (HRQOL)-related studies on AIS patients greatly improves and complements the interpretations on patients' appearance which endeavors further research on cognitive behavior in AIS patients after years of surgery in long-term follow-up studies.