Abstract： Objective:To explore the application and clinical efficacy of ultra microsurgical techniques during replantation of severed fingers in Yamano I region in children.Methods:From January 2020 to November 2022, the relevant clinical data were retrospectively reviewed for 7 boys undergoing Yamano I single finger replantation. The median age was 5.6(2-12) year. Ultra microsurgical techniques were employed for anastomosing the arteries and veins for finger replantation. Symptomatic measures of anti-infection, anti-vascular embolism and anti-vascular spasm were offered postoperatively. The treatment outcomes were tracked through outpatient visits, telephone calls and WeChat.Results:All severed fingers survived after replantation. One case of vascular and arterial crisis was relieved after spasmolytic treatment. Another case of vascular and venous crisis recovered after lateral incision hemorrhage. The follow-up period was (6-18) months. The surviving fingers had no deformities. There were plump appearance, red color and full texture. Nail bed remained intact and flexion and extension activities of finger joints normalized. According to the evaluation criteria of Chinese Society of Hand Surgery for upper extremity function, the outcomes were excellent (n=6) and decent (n=1). And the excellent-and-decent rate was 100%.Conclusion:Application of ultra microsurgery technology may complete the replantation of severed fingers in Yamano I area in children. Capable of improving the survival rate of replantation, such a procedure achieves a pleasant appearance with an excellent functional recovery.