Objective To investigate the effects of enhanced recovery after surgery (ERAS) on postoperative function and pain in total hip arthroplasty (THA) patients with high comorbidity. Methods Patients with THA who were admitted between January 2020 and January 2022 were selected as the study objects, and a total of 223 patients with high comorbidity met the selection criteria. Patients were randomly divided into two groups using the random envelope method. During perioperative period, 112 cases in the ERAS group were treated according to the ERAS protocol and 111 cases in the control group with the traditional protocol. There was no significant difference in gender, age, body mass index, Charlson comorbidity index, preoperative diagnosis, the type and number of the comorbidities, preoperative visual analogue scale (VAS) score between the two groups (P>0.05). However, the Harris score of ERAS group was significantly lower than that of control group before operation (P<0.05). Preoperative and postoperative hospital stays were recorded. The VAS score was used to evaluate the pain before operation, at 1 day after operation, at the leaving bed time, at the day after discharge, and at 2 weeks after operation. Harris score was used to evaluate hip function before operation and at 2 weeks, 1 month, 3 months, 6 months, and 12 months after operation. The incidence of complications, 30-day readmission rate, mortality rate, and patient’s satisfaction were recorded. Results The length of preoperative hospital stay in ERAS group was significantly shorter than that in control group (P<0.05). But there was no significant difference in the length of postoperative hospital stay between groups (P>0.05). All patients in the two groups were followed up 12 months. The VAS score in the two groups after operation was lower than that before operation, and showed a gradually trend with the extension of time, with significant differences between different time points (P<0.05). VAS scores of ERAS group were significantly lower than those of control group at different time points after operation (P<0.05). The postoperative Harris scores in both groups were higher than those before operation, and showed a gradually increasing trend with the extension of time, with significant differences between different time points (P<0.05). Harris scores of ERAS group at 2 weeks, 1 month, and 3 months after operation were significantly higher than those of control group (P<0.05). Complications occurred in 2 cases (1.79%) of the ERAS group and 6 cases (5.41%) of the control group, with no significant difference in incidence (P>0.05). In the control group, 1 case was readmitted within 30 days after operation, and 1 case died of severe pneumonia within 1 year of follow-up. There was no readmission or death in ERAS group, and there was no significant difference in the above indexes between the two groups (P>0.05). At last follow-up, the satisfaction rate of patients in ERAS group was slightly higher than that in control group, but the difference was not significant (P>0.05). Conclusion For THA patients with high comorbidity, ERAS protocol can shorten preoperative waiting time, better reduce pain, and improve hip function.