Abstract: Objective To study the therapeutic effect of XL-radiofrequency ablation under microscope on facial flat wart. Methods Fortyfive patients with flat wart (13 males and 32 females) aged 16~68 years with a disease course of 3 months~10 years, who visited the Outpatient Department in our hospital from June 2006 to August 2011, were included in this study. The number of flat warts in each patient was 4 to 110 and ≥ 10 in 31 patients. The largest flat wart was 60 mm×30 mm. The flat warts were treated once by XL-radiofrequency ablation under operating microscope. The patients were followed up for 6 months~2 years, during which relapse of the disease, pigmentation and scar formation were observed. Results The facial flat warts were cured in 43 out of the 45 patients.The number of facial flat warts was markedly reduced in 2 patients with mild pigmentation and no scar formation. Conclusion The curative rate of XL-radiofrequency ablation under operating microscope for facial flat warts is high with no scar formation.