Objective To explore the characteristics and clinical application of the anterolateral thigh flap pedicled with the oblique branch in the intramuscular of lateral circumflex femoral artery. Methods The clinical data of 25 patients with skin and soft tissue defects of extremities admitted between December 2020 and April 2021 were retrospectively analyzed, including 16 males and 9 females, aged 14-75 years, with the median age of 43 years. The defect site included 13 cases of hand, 2 cases of forearm, 2 cases of calf, and 8 cases of foot and ankle. The wound area ranged from 6 cm×4 cm to 35 cm×22 cm. Twenty-four patients with trauma were admitted to hospital immediately after injury, and 1 patient with diabetic foot infection was transferred to the hospital after ineffective treatment in other hospital. Flap surgery was performed from 0 to 56 days (median, 22 days) after admission. A total of 26 thigh flaps were harvested in 25 patients, with unilateral flaps in size of 7 cm×5 cm to 40 cm×10 cm. The type, caliber, and location of the perforating branch were recorded during the operation, and the anatomical characteristics of the oblique branch of the intramuscular trunk were mainly observed. The flap harvesting time was recorded; the flap survival and wound healing time were observed; at last follow-up, XIAO Feipeng et al. flap comprehensive efficacy evaluation table was used to evaluate the effectiveness of flap repair from three aspects of donor site, recipient site, and subjective satisfaction of doctors and patients. Results After the oblique branch in intramuscular of lateral circumflex femoral artery was sent out, it ran 2-3 cm obliquely laterally and inferiorly in the intermuscular septum and then entered the vastus lateralis muscle, and sent out perforating branches to nourish the skin. A total of 61 perforating branches were marked in 26 thighs of 25 patients before operation, and 70 perforating branches were found during operation, including 9 transverse branches, 29 descending branches, and 32 oblique branches, all of the oblique branches were musculocutaneous perforators. All 25 patients were followed up 6-10 months, with an average of 8 months. The time of unilateral thigh flap harvesting ranged from 13 to 90 minutes, with an average of 48 minutes. One patient with diabetes developed disturbance of blood supply and complete necrosis of the flap at 1 month after operation, and then the flap was repaired with skin graft; 1 case developed arterial crisis after operation, which survived after timely exploration; and the rest of the flaps survived smoothly. The wound healing time of the recipient site ranged from 10 to 44 days, with an average of 19 days, and the donor site of the thigh healed by first intention. At last follow-up, the color and texture of the flap was good and the sensation recovered to S1-S2. Only linear scar was left in the donor site, no scar contracture, pain, and other discomfort occurred, and no other serious complications occurred. Evaluated by flap comprehensive efficacy evaluation table, the score was 74-93, with an average of 88, of which 10 cases were excellent, 13 cases were good, and 2 cases were fair, with an excellent and good rate of 92%. Conclusion The intramuscular trunk oblique branch is not uncommon, and its trunk course and perforators distribution are regular. To improve the understanding of this type of oblique branch and adopt appropriate methods during operation can improve the success rate of skin flap extraction.