Abstract: With the development of deep submicron technology，Network on Chip（NOC） has already become a hot topic.The sharp increase of transistors per unit area takes a challenge to the reliability of NOC.When the node or link fault occurs，how to achieve fault-tolerant and improve reliability have already become the main point of NOC design.By the introduction of NOC fault-tolerant，using current mesh topology and dimension-ordered routing algorithm，this paper proposes a new fault-tolerant routing in mesh based on priority（PR），then does performance comparison with OPNET.