Abstract: The flow quality of the linear cascade tests for compressor airfoils is always poor under high-load conditions, it is necessary to improve flow quality of linear cascade by adjusting methods to ensure the availability of test data. A passive control scheme of adjustable tailboard was designed based on a subsonic plane cascade wind tunnel, and the effect of tailboard angle on flow quality and performance of cascade was investigated, and compared with the results of active control scheme of upper end-wall suction previously studied. The results indicate that the inlet and outlet flow quality of subsonic linear cascade can be adjusted by tailboards for which changing the static pressure distribution at cascade exit. As the tailboard angle decreases, the exit static pressure of cascade near the upper tailboard decreases, while the exit static pressure near the lower tailboard increases. Reducing the tailboard angle is conducive to improving the flow quality of cascade, but there is a critical value of tailboard angle at which both the inflow and outflow quality of cascade are good, and the loss and exit flow angle show good periodicity. And the periodicity of outlet flow angle shows best due to the isolating effect of tailboard, and the periodicity index of outlet flow angle is less than one. The flow quality of cascade declines when over the critical value. The improvement of inflow quality of cascade by upper end wall suction is better than that of tailboard. Due to the difference of control mechanism and flow quality between these two methods, the outlet flow angle of cascade adjusted by tailboard is about 2° smaller than that of upper end wall suction, and the loss is about 0.02 larger than that of upper end wall suction, and the difference of static pressure ratio and distribution of isentropic Mach number is small.