A method for setup of a network device and a system thereof are provided. The method is operated in a gateway device in a LAN. In the method, a software sequence operated in the gateway device receives packets generated by a terminal device in the LAN. After analyzing the packets, a message for triggering a setting process is generated if an event in compliance with a trigger condition is determined from the packets. The message for triggering a setting process is transmitted to a default setup device. The setup device is such as a computer device that allows the user to set up parameters according to an event requirement. When the network device receives the parameters, a corresponding function in the network device is re-activated.