Objective To explore the diagnostic value of urodynamic parameters for bladder outlet obstruction (BOO) in patients with benign prostatic hyperplasia (BPH) combined with lower urinary tract symptoms (LUTS). Methods Clinical data were retrospectively collected from 150 patients with BPH-associated LUTS who were treated in the Department of Urology, Xinjiang Production and Construction Corps Hospital, from January 2023 to December 2025. Patients were assigned to the BOO or non-BOO group according to comprehensive clinical assessment, supplemented by postoperative follow-up findings. Urodynamic parameters were compared between the two groups. Spearman correlation analysis was used to assess the associations between key urodynamic variables and BOO status. Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic performance of individual parameters and their combination. Results There were no significant differences in age, body mass index (BMI), disease duration, prostate specific antigen (PSA) level, or prostate volume between the two groups (all P＞0.05). Compared with the non-BOO group, the BOO group showed higher maximum detrusor pressure (P_detmax) and detrusor pressure at maximum flow (P_detQ_max), together with a lower maximum urinary flow rate (Q_max) (all P＜0.05). P_detQ_max was positively correlated with BOO status (P＜0.05), whereas Q_max was negatively correlated with BOO status (P＜0.05). ROC analysis showed that P_detQ_max had good diagnostic performance as a single parameter. Its diagnostic performance improved further when combined with Q_max. Conclusion Pressure-flow urodynamic parameters provide objective information for evaluating BOO in patients with BPH and LUTS. P_detQ_max has favorable individual diagnostic value, and its combination with Q_max may improve the diagnostic performance of BOO and support clinical stratification and individualized treatment decisions.