Abstract <p>In this paper, we consider the proposed method for identifying the average integral heat transfer coefficient of an axial heat pipe (ATT) coolant to a capillary—porous wick as a function of temperature. The purpose of axial heat pipes is to divert thermal energy from the heat-generating equipment and redistribute it over the surface of the radiator to ensure the regular functioning of the thermostatically controlled equipment. This problem is solved by determining the global extremum of the RMS functional of the discrepancy between the theoretical and experimental temperature field at the temperature sensor installation sites. The method of thermal balances was chosen as a method for solving the “direct” problem of heat transfer inside a heat pipe, and the gradient method of conjugate directions was chosen as an optimization method, as the most accurate method of the first order of convergence of the iterative process. As a criterion for stopping the iterative process, a superposition of errors is used that introduce incorrectness into the studied formulation of the heat transfer problem, such as systematic, error in the formulation of the “direct” heat transfer problem, etc. The resulting identified solution is compared with the classical experimental method for determining the heat transfer coefficient based on the analysis of thermal resistances of the structure.</p>