In response to the thermal characteristic issues of the high-pressure hydraulic system of civil aircraft in low-temperature environment, this paper takes the pipeline system as the starting point, theoretically studies the heat generation, heat dissipation, and other mechanisms of the pipeline system, and establishes a theoretical model for the thermal characteristic of the pipeline system. In order to conduct the thermal characteristic experiment of the high-pressure pipeline system, a hydraulic system test bench is set up to obtain test data of the pipeline system in low-temperature environment through testing. By analyzing and calculating the test data, the pressure drop and temperature variation characteristics of the pipeline system in low-temperature environment are understood, and engineering values of the resistance coefficient along the pipeline, local resistance coefficient, and overall heat transfer coefficient for theoretical calculations are obtained, providing a basis for the thermal characteristic analysis of hydraulic systems in civil aircraft.