Abstract: Four triangle mechanical tabs with different area and vertex angle,fixed on the exit of primary nozzle,have been tested comparatively to investigate the effect of number,area(or blockage ratio),shape and fixed angle of the tabs on the aerodynamic characteristics of the exhaust ejector mixer system.The results show that the application of the mechanical tabs increases the system pressure loss coefficient,but it can improve system pumping coefficient and mixing uniformity,and meliorate the synthetic aerodynamic characteristics of the exhaust ejector mixer system.