Abstract: The quartz lamp radiation heater is the most widely used for the aerothermal simulation in the thermal tests for structures. The determination of the radiation flux field of the quartz lamp heater is essential for improving the test accuracy, as well as evaluating the testing results and validating the structural design. The applicability of various models for calculating the radiation flow field is discussed, as well as the characteristics of the radiation flux field in the quartz lamp heater. The computational accuracy and the applicability of several kinds of radiation calculation software are analyzed comparatively through theoretical analyses, tests and simulation examples. The application strategies for each kind of software are given, to provide some reference to determine the environment in thermal tests quickly and accurately.