Objective:To investigate the effect of early gradual diet on reducing delirium in elderly patients with hip arthroplasty.Methods:From January 2018 to January 2020, 74 cases of hip arthroplasty patients aged over 65 years old who were treated in the Third Affiliated Hospital of Sun Yat-sen University were selected as the observation objects. They were randomly divided into experimental group and control group with 37 cases in each group. The experimental group was given early gradual diet on the basis of routine postoperative care, while the control group was given routine postoperative diet on the basis of routine postoperative care. The incidence of postoperative delirium, Pittsburgh Sleep Quality Index (PSQI), patient satisfaction rate, average hospitalization days and average hospitalization expenses were used to evaluate the effect of early gradual diet on reducing delirium in elderly patients with hip arthroplasty.Results:The incidence of delirium in the experimental group was 2.70% (1/37) and 16.22% (6/37) in the control group, the difference was statistically significant ( χ2 value was 3.945, P<0.05); the hospitalization days of the experimental group were (10.68±5.13) d, (13.62±7.19) d in the control group. The difference of hospitalization days was statistically significant ( t value was 2.877, P<0.01). The incidence of difficulty in falling asleep and the satisfaction rate of the experimental group were 8.11% (3/37) and 94.59% (35/37) respectively, and those in the control group were 29.73% (11/37) and 78.38% (29/37) respectively, and the differences were statistically significant ( χ2 value was 5.638, 4.163, P<0.05). Conclusions:Early gradual diet after operation can reduce the incidence of delirium in elderly patients with hip arthroplasty, shorten the average hospitalization days, reduce the incidence of difficulty in falling asleep, improve patients' satisfaction, and help patients to pass through the perioperative period more safely and comfortably.