A method and device for determining a route including: presetting the number N of routes, performing a K shortest paths algorithm after a route query request is received, calculating the routes by group according to the number N of the routes, whenever N routes are calculated, outputting the N calculated routes as a group, and assigning resources to the group of routes; and stopping calculating the routes if a route on which resource matching is successful is obtained from the group of routes, and using the route on which the resource matching is successful as the determined route; otherwise, performing the resource matching on the next group of output routes to determine a route; where N is a positive integer and 1