BACKGROUND Urodynamics is the gold standard for evaluating the function of neurogenic bladder after spinal cord injury (SCI), but there are few studies on urodynamics in patients with complete and incomplete suprasacral SCI in different periods.There is a lack of sufficient evidence for the timing of the first urodynamic examination. METHODS The urodynamic results of 101 patients with complete and incomplete suprasacral SCI at 0-30, 31-60, 61-90, and 91-365 days after injury were included. Urodynamic parameters were compared between 0-90 and 91-365 days, including detrusor overactivity (DO), bladder compliance (BC), bladder-filling sensation, maximum cystometric capacity (MCC), detrusor external sphincter dyssynergia (DESD), maximum urinary flow rate (Qmax), detrusor pressure at a maximum urinary flow rate (PdetQmax). RESULTS There were 45 patients with complete SCI and 56 with incomplete SCI. With the course's prolongation, the proportion of DO increased gradually in patients with complete and incomplete injury within 90 days, while the MCC gradually decreased. The bladder-filling sensation of patients with complete SCI is mostly absent. Significant differences were found between 0-90 and 91-365 days in terms of DO, DESD, MCC, Qmax, and PdetQmax incomplete SCI, and DESD in incomplete SCI, and between complete and incomplete SCI in terms of DO, bladder filling sensation, MCC, Qmax, PdetQmax at 0-90 days after injury, and bladder filling sensation at 91-365 days after injury. CONCLUSIONS Urodynamic examination should be conducted as soon as possible after injury in patients with incomplete suprasacral SCI, while for those with complete injury, the urodynamic examination can be initiated following clinical symptoms within 90 days after injury.