In district heating (DH) systems, the transmission and distribution process occupy large amount of energy consumption. Hydraulic and thermal imbalance in pipe networks often lead to uneven heating, affecting user comfort and resulting in energy losses. To solve this problem, this study investigates the root causes of hydraulic and thermal imbalances in DH systems. Key factors have been identified such as initial flow rates, initial loads, and positions in the network of end-users. And the relationship between hydraulic and thermal imbalances have been analyzed. Building on this analysis, we further propose a novel strategy for differential pressure set-point adjustment. This strategy is developed based on a quantitative understanding of the flow rate changes and positions of end-users. It aims to rectify imbalances efficiently, thus enhancing the overall performance of the network. The effectiveness of the proposed strategy is validated through comparative analysis with the conventional constant differential pressure (CCDP) control strategy and an exist variable differential pressure (VDP) control strategy. Results demonstrate significant improvements in network performance, including enhanced stability and reduced energy losses. The proposed strategy reduces the average pressure difference in the main pipe by up to 10.9 %, improves the supply and return temperature difference by 10.9 %, and maintains valve openings above 70 % during peak periods. Additionally, it achieves 23.5 % energy savings in transmission and distribution, highlighting its potential to enhance system performance and efficiency. In addition, this strategy is more in line with the actual situation of end-user demand change for valve adjustment.