Provided are an intelligent network monitoring system and a working method thereof. According to the network monitoring system and the working method of the network monitoring system, the operation states of multiple pieces of network equipment can be intelligently and automatically detected, when a network failure occurs, warning information can be sent out through a mobile network, and the working efficiency can be greatly increased. Network monitoring devices are connected to the network equipment respectively. The network monitoring devices comprise hardware modules and software modules. The hardware modules comprise control units and short message transmitters. The control units comprise CPUs, FLASH storages, internal storages, serial ports, serial port drivers, network interfaces and USB interfaces. The CPUs are provided with I/O interfaces and the serial port drivers are connected with the serial ports. The intelligent network monitoring system and the working method of the intelligent network monitoring system greatly increase the working efficiency, effectively prevent the software modules from being trapped in an endless loop, and therefore continuous work of the system is further guaranteed.