The invention relates to a wireless communication network system. A construction worker is capable of editing warning information through a handheld device, so a vehicle equipped with a vehicle-mounted client in a certain distance can receive the warning information through a wireless module of the vehicle-mounted client. After processing of a single chip microcomputer, the warning information is displayed on a display screen to inform a driver of slowing down or no entry in front, thereby reducing or avoiding traffic accidents caused by factors like road maintenance. When a traffic accident occurs or a driver passes a car accident place, the vehicle-mounted client is capable of communicating with a network access device A of a server end A through a GSM or a GPRS module to send the car accident information to a rescue reception desk server. When car accidents or other reasons cause front road jams in a certain region range, a network access device A in a server end B sends the road jams or blocking information to the display of the vehicle-mounted client through a GPRS and the GSM or GPRS module in the vehicle-mounted client.