Typical schemes that exploit semiconductor optical amplifier cross-phase modula tion (SOA-XPM) to constitute all-optical XOR l ogic gate need to precisely control the phase of the MZI due to the inherent properties of XPM in SOAs.In t his paper,a scheme of all-optical XOR logic gate based on MZI and XPM in cascaded SOAs is proposed.The scheme con sists of a symmetrical SOA-MZI by putting two cascaded SOAs on both arms of the MZI,and the gate can be realized via the configuration and the injection of the clock signal and two input signals.Numer ical simulations at 40Gbit/s demonstrate that the quality of the output is ensured as long as the splitting r atio of the two input signals is reversed.Since the splitting ratio can be varied in a large extent,this scheme provides the advantage of lowering the requirement in precisely controlling the phase when exploiting XPM in SOAs. Thus,all-optical XOR logic gate with broad phase margin is constructed.Finally,we discuss the influence o f clock pulse power and splitting ratio of input signals on logical operation results.It is found that asynchrono us change of input signals′ splitting ratio will relatively affect the quality of output signals.Besides,the methods to enhance processing speed are discussed.