What is already known about this topic? Day surgery is conducted worldwide due to its time-saving, cost-effectiveness and low risk for post-operative infection. Delayed discharge is considered as one of the most important indicators for healthcare quality of a day surgery centre. Most of the identified risk factors for delayed discharge are from the developed countries' experience of day surgery and remain controversial. What this paper adds? The insurance reimbursement rate influenced patients' willingness for discharge. Living in the same city where the hospital is located was a protective factor for delayed discharge. Post-operative metabolic disorder was a risk factor for delayed discharge. The implications of this paper: Reducing the insurance reimbursement rate of patients who meet discharge criteria but ask for longer hospital stays may be helpful to reduce delayed discharge. Careful monitoring and rapid response to post-operative complications may be simple but useful measures to reduce the risk of delayed discharge.