Abstract: For use in a dual-path network system comprising a master end, a main transmission path, a sub-transmission path, an intermediary device, and a slave end, a network redundancy check application program management method is disclosed to virtualize COM ports of multiple IP addresses in the master end into one single virtualized COM port by means of a driver in the master end so that the user/user's application program needs only to manage/monitor the virtualized COM port. Through the driver and the firmware formed in the intermediary device, the invention covers all operation modes, and the user/user's application program needs not to worry about system complication resulted from the redundancy check system. Under the network architecture of the present invention, the master end enjoys the high stability of dual-path, and the manager needs not to manage a big number of COM ports.