Abstract: In order to study and optimize the support interference characteristics for the single support rod in the FL–51 low-speed wind tunnel, the longitudinal and transverse two-step support interference test of the aircraft in cruise and uplift configuration is carried out for the three-dimensional support rods with the cross section of 24 ribbed, round and truncated airfoil at the wind speed of 70, 50 m/s and the support rod pre-deflection angle of 11° （the angle between the support rod and the axis of the model fuselage is 79°）. Based on the study of the support interference characteristics of the single support rod at the pre-deflection angle of 11°, the support interference characteristics wind tunnel test of 24 ribbed, round and truncated airfoil support rods was carried out at the pre-deflection angle of 30° and 60° （the angle between the support rod and the axis of the model fuselage is 60° and 30° respectively）. For further analyzing the characteristics of two-dimensional support rod flow around and wake characteristics with different sizes and cross section shapes, the wind tunnel PIV test is carried out. The results show that the longitudinal support interference of the airfoil support rod is the best, but it deteriorates in the transverse direction.With the increase of the maximum thickness, the wake vortex of the airfoil support rod has good consistency, and the wake vortex of the 24 ribbed and round cross section support rod varies with diameter. For wind tunnel tests that only conduct longitudinal tests or focus on longitudinal tests, airfoil cross section or truncated airfoil should be selected.