An investigation was conducted on the oscillation characteristics of shock train in deflected center-line isolator by using unsteady numerical simulation methods. The effects of back-pressure of isolator exit and expanded ratio of isolator on the oscillation characteristics of shock train were analyzed. The results show that the peak exit total pressure corresponds to the smallest displacement of the shock train leading edge and the valley exit total pressure corresponds to the largest displacement. The further research indicates that the self-excited oscillation of shock train in isolator only occurs under several back-pressure conditions and the shock train keeps steady under high back-pressure finally. Compared with the straight isolator

the shock train self-excited oscillation is prone to occur in deflected center-line isolator under the same incoming flow Mach number of 2.0. In addition

under the same back-pressure condition

the larger expanded ratio(eg.37%) means the lower oscillation frequency

amplitude and time-mean exit total pressure the flow field can be got when the self-excited oscillation phenomena occurs.