Method, device and system for selecting route

The invention relates to a method, a device and a system for selecting a route. The method for selecting the route comprises the following steps: receiving a data request which comprises target data information; generating assessment command information according to the target data information, and sending the assessment command information to a neighbor node; waiting to receive response information returned by the neighbor node, judging whether the response information contains first response information which is the response information on finding target data, and obtaining cost informationand target node information which are carried by the first response information if the response information contains the first response information; and selecting the optimum route between an initiated node and a target node from a network topology graph according to the cost information and target node information, wherein the target node is the node where the target data exists. The method, thedevice and the system achi