Objective To investigate the efficacy and safety of small incision drainage in the treatment of axillary osmidrosis after small skin incisions along the axillary lines and ultra-thin flap method. Methods From February 2018 to September 2023, 70 patients with axillary osmidrosis who successfully completed the operation of small skin incisions along the axillary lines and ultrathin flap in our hospital were selected as the research objects. They were randomly divided into control group and study group, with 35 patients in each group. The control group was treated with traditional drainage, and the study group was treated with small incision drainage. The subcutaneous hemorrhage score, clinical efficacy and complications were compared between the two groups. Results The subcutaneous hemorrhage score of the study group was lower than that of the control group at 1 and 2 days after operation, and the difference was statistically significant (P <0.05). The total effective rate of treatment in the study group was 97.14%, which was higher than 82.86% in the control group, and the difference was statistically significant (P <0.05). The incidence of complications in the study group was 2.86%, which was lower than 20.00% in the control group, the difference was statistically significant (P <0.05). Conclusion Small incision drainage in the treatment of axillary osmidrosis after small skin incisions along the axillary lines and ultra-thin flap method can alleviate subcutaneous hemorrhage, improve the overall treatment effect, and reduce the incidence of complications. It has good efficacy and safety.