The Z-type parallel multi-branch pipe groups are widely utilized to deliver fluid in cooling high-power electronic equipment. The CFD software is commonly used to perform numerical simulations of these systems. This study examines the effects of varying inlet flow rates, branch pipe diameters, and main pipe diameters on flow characteristics and heat transfer. The flow deviation coefficient and temperature distribution were used to assess the flow uniformity in branch pipes and the heat transfer efficiency of cold plates. The findings reveal that increasing the inlet flow rate enhances flow inhomogeneity but decreases the overall temperature of the cold plate. Similarly, increasing the branch pipe diameter strengthens flow inhomogeneity without significantly affecting the cold plate's temperature distribution. Conversely, increasing the main pipe diameter exacerbates the uneven flow distribution and results in more local hot spots on the cold plate. Based on these simulation results, an optimized design for Z-type parallel multi-branch pipe systems can be developed to improve flow uniformity and heat transfer efficiency.