Abstract: To investigate the energy loss characteristics of disk pumps during operation, numerical simulations were conducted to analyze the entropy production rates and total entropy production values in the volute, impeller, inlet, and outlet regions and to identify the main causes of energy loss within the pump. The results show that turbulent entropy production dominates total entropy production, accounting for approximately 90% of the total within the pump and far exceeding direct entropy production. The total entropy production in the impeller region is significantly higher than that in the other flow-passage components, accounting for approximately 70% of the total, while the volute region ranks second, contributing about 25%. As the flow rate increases, total entropy production in both the impeller and volute regions increases. Total entropy production in the impeller region remains higher than that in the volute region, indicating that the impeller is the primary region of energy loss in the disk pump. As the flow rate increases, the proportion of total entropy production attributable to the inlet section first increases and then decreases, whereas the proportion attributable to the outlet section continues to increase. Under most flow conditions, total entropy production in the bladeless region is higher than that in the bladed regions adjacent to the front and rear cover plates. At low flow rates, turbulent entropy production in the bladed region adjacent to the rear cover plate is higher than that in the corresponding region adjacent to the front cover plate. Once the rated operating condition is reached, turbulent entropy production in the bladed region adjacent to the front cover plate exceeds that in the corresponding region adjacent to the rear cover plate. This study clarifies the key regions of energy loss within disk pumps and the mechanisms responsible for these losses, providing a theoretical basis for optimizing the hydraulic performance of disk pumps.