A ring-based network and a construction method thereof, comprising a plurality of nodes and a plurality of links. In an initial status, each node compares each first link-up packet and fills a priority value in the first link-up packet with the higher priority value to form a second link-up packet. The priority value of each node and the highest priority value of each adjacent node recorded in each node are compared with each second link-up packet. When the priority value of the node and the highest priority values of adjacent nodes recorded in the node are smaller than the second link-up packet, the ring port of the node is situated at a forward status. According to the forward status or a blocked status of the ring port, these links form a plurality of forward links and a blocked link respectively.