To analyze the surgical efficacy of patients with mixed hearing loss and otosclerosis with different air bone gap (ABG) before surgery, and to provide reference for the prognosis evaluation of otosclerosis surgery. The clinical data of 108 cases(116 ears) of otosclerosis who had undergone stapes fenestration technique artificial stapes implantation in Xiangya Hospital of Central South University from November 2013 to May 2020 and had mixed hearing loss before surgery were collected, including 71 women(76 ears)and 37 men (40 ears), with an average age of 38.5 years. According to preoperative pure tone audiometry ABG, they were divided into three groups: group S, 15 dB≤ABG<31 dB, a total of 39 ears; group M, 31 dB≤ABG<46 dB, a total of 58 ears; and group L, ABG≥46 dB, 19 ears in total. The hearing outcomes of three groups of patients at 6-12 months after surgery were compared and analyzed using SPSS 24.0 statistical software. A total of 3 patients (group S: 2 cases; group L: 1 case) experienced severe sensorineural hearing loss after surgery and were not included in the statistical analysis. After surgery, the pure tone hearing threshold of patients with otosclerosis in each group was significantly improved compared to before surgery, with an average air conduction threshold improvement of(21.6±13.4) dB. The difference between before and after surgery was statistically significant(=17.13, <0.01). The average bone conduction threshold improved by(3.7±7.6) dB, and the difference was statistically significant before and after surgery(=5.20, 0.05). The postoperative ABG in group S was the smallest[(16.5±9.0)dB], while in group L, the postoperative ABG was the largest[(20.5±10.0)dB]. Compared with group S, group M and group L still had a large residual ABG at 2 000 Hz after surgery. The bone conduction threshold of both S and M groups improved to some extent after surgery compared to before (<0.01). Surgery can benefit patients with mixed hearing loss and otosclerosis with different preoperative ABG. Patients with small preoperative ABG have better surgical results and ideal ABG closure at all frequencies after surgery. Patients with large preoperative ABG can significantly increase the gas conduction threshold during surgery, but certain frequencies of ABG may still be left behind after surgery. The improvement effect of surgery on bone conduction threshold is not significant. Patients should be informed of treatment methods such as hearing aids based on their actual situation for selection.