Abstract: Low speed wind tunnel oscillation test is an essential test research project for the development of aircraft, especially in the development of the aircraft with the capability of post stall maneuver. At home and abroad, the oscillation tests have been carried out in low speed wind tunnel. Experimental study has also been conducted on oscillation and other dynamic system to test the support interference and wall interference; however, the modifications for the support interference have not been studied in low speed wind tunnel oscillation test. In order to improve the accuracy of low speed wind tunnel oscillation test, to understand the mechanism of the support interference in low speed wind tunnel oscillation test, to provide high quality data for accurate prediction of aerodynamic characteristics and highly reliable performance analysis, to improve the logistic security level for aircraft development, the support interference was measured in FL-51 wind tunnel by single degree of freedom oscillation test with a two-steps method for three modes, i. e., pitch, roll and yaw. The two-step method for the support interference correction adopts the principle of superposition. The influence effect of the auxiliary support bracket, the main bracket and image model of aerodynamic forces are linear superposition in this method, without considering the mutual interference among different frames. With the aid of particularly designed and processed support frame and the image frame, the influence of the single degree of freedom oscillation was obtained by the two-step test. It is found that the influence of the support increases with increasing frequency, and the support has significant influence on the accuracy of the single degree of freedom oscillation test. When a large oscillation test is performed, the corresponding support interference test is required. The results show that the two step method can be used to modify the disturbance caused by the bracket, and the accuracy of the test results can be improved.