The structures and working operations of SOA-assisted Sagnac XOR gate, all-optical MZI XOR gate and the SOA-assisted bidirectional data input XOR gate were analyzed, then the three XOR’s performance and the complexity of the system were compared. Based on it, a modified SOA-MZI-based all-optical XOR logic gate was proposed. The feasibility of the program was analyzed. Finally, the optical principle and mathematical model of the program were discussed. Values analysis shows that the program can effectively achieve the XOR function, and appropriately adjust the parameters, the system performance will be superior to the existing XOR gate.