To explore clinical effect of the first metatarsophalangeal joint fusion combined with lateral toe rotation Weil osteotomy in treating hallux valgus with severe metatarsal adduction. From March 2017 to August 2021, 37 patients ( 69 feet ) with severe plantar adductor hallux valgus were treated with the first metatarsophalangeal joint fusion combined with rotational Weil osteotomy were retrospectively analyzed, including 8 males(11 feet) and 29 females (58 feet), aged from 67 to 83 years old with an average of (70.03±2.87) years old;3 cases on the left side, 2 cases on the right side and 32 cases on both sides. Visual analogue scale(VAS) was used to evaluate degree of pain relief before operation, 6 weeks after operation and at the final follow-up. American Orthopaedic Foot and Ankle Surgery (AOFAS) forefoot score was used to evaluate function of the affected foot before operation and final follow-up. Hallux valgus angle(HVA) and intermetatarsal angle(IMA) were measured before operation and at the final follow-up. Thirty-seven patients(69 feet) were followed up from 12 to 48 months with an average of(22.8±0.6) months. Bone healing was achieved at the first metatarsophalangeal joint from 7 to 10 weeks with an average of (8.00±1.21) weeks after operation, without delay and nonunion. HVA was increased from (44.30±2.84)° before operation to (15.20±2.13) °at the final follow-up, and had statistical difference(t=65.781, P<0.05);while no difference in IMA before and after operation(P>0.05). VAS was decreased from (6.73±1.48) points to (2.78±0.71) points at 6 months after operation(t=3.279, P<0.05), and had difference compared with the latest follow-up(1.16±1.12)(t=4.859, P<0.05). AOFAS forefoot score increased from (52.14±5.78) preoperatively to (86.70±4.86) at the fonal follow-up, and 25 feet got excellent results, 40 feet good and 4 feet fair. The first metatarsophalangeal joint fusion combined with lateral toe rotation Weil osteotomy in treating severe plantar adduction hallux valgus could significantly relieve pain and appearance of forefoot, stabilize the first sequence, and significantly improve walking function.