[Abstract] Objective To investigate the diagnosis, postoperative tuning and hearing and speech rehabilitation effects of cochlear implantation in children with Common Cavity malformation of the inner ear. Methods A retrospective analysis of 19 children with prelingually deaf cochlear implants with preoperative imaging confirmed Common cavity inner ear malformation, and intraoperative assessment of the auditory nerve pathway using electrical stimulation of auditory brainstem evoked potentials (EABR) as an aid; and screening of 19 prelingually deaf children with cochlear implants of normal cochlear structures with similar clinical data were paired to analyze the preoperative hearing, speech and postoperative tuning data; a follow-up questionnaire was conducted for the The children’s guardians were followed up with questionnaires, and the dynamic range of T and C values, categories of auditory performance (CAP) and speech intelligibility rating (SIR) were examined statistically in the two groups at postoperative start-up and 6-month start-up. scores. Results: The T value of the Common cavity inner ear malformation group (172.59 12 hal’> 14.57) was significantly higher than that of the control group (139.63 12 hal’> 19.45) (P<0.05), and there was no significant difference in dynamic range (P>0.05); postoperative CAP and SIR values showing the results of auditory speech rehabilitation (5.50 12 hal’> 0.94 and 3.00 12 hal’> 0.94, respectively) and 3.00 12 hal’> 0.82, respectively) scored lower than the control group (6.90 12 hal’> 0.77 and 3.90 12 hal’> 0.57) (P<0.05), but were significantly higher than preoperatively. Facial nerve twitching due to electrical stimulation occurred in some children at the time of switch-on (31.58% of facial twitching). Conclusion: Common cavity is a serious type of inner ear malformation, and EABR aids in preoperative comprehensive evaluation, selection of appropriate surgical method, postoperative personalized power-on, tuning and long-term auditory speech reinforcement training, children's auditory speech ability can be restored to different degrees; the postoperative results vary greatly and are overall significantly worse than those of the same condition without cochlear malformation. [Keywords] Common Cavity malformation, cochlear implantation, efficacy, rehabilitation