Abstract: The test facility of 2-D supersonic-supersonic ejector was constructed. Varieties of tests were carried out to investigate the starting and load characteristics of a second throat ejector. The schlieren photographs of the mixing chamber flow field were got by schlieren apparatus synchronously. The experimental results show that there are shocks brought by background pressure in mixing chamber fore part while the ejector starts critically.It is possible that the main shocks originate from the mixing chamber rearward while the ejector starts completely. Secondary flow has booster action for ejector starting which can make shocks to move backward in evidence. As the secondary flow is injected, the mixing layer between primary and secondary flow will occur obviously. If the pressures of primary and secondary flow are not matched, a strong oblique shock wave will be formed at nozzle exit inwall, which will be reflected between the wall and mixing layer, then the capability of primary flow will be reduced.