Abstract: The near wall flow field of a highsubsonic flow simulation facility, which is used in thermal effect research of laser irradiation experiment, was calculated using CFD, and comparison of flow quality for planar and arc wall of the target material with and without side plate shows that a semiopen channel formed by side plates and the target material wall will give a broader uniform flow area in the test section. The flow measurements of the simulation facility, which was built up according to the optimized parameters based on CFD, yield good agreement with numerical results, and the flow quality can meet the requirements of laser irradiation thermal effect experiments.