Path calculation method and device

The invention discloses a path calculation method and a path calculation device. The method comprises the following steps of: performing simplification operation on multi-link topology to obtain single-link topology, and calculating a path in the single-link topology; and after a path output result is selected in the calculated path, forming an expanded path passing through the same nodes as the path output result according to multiple links among nodes in the multi-link topology, and continuously selecting a path output result from the expanded path or the calculated path. The K-shortest path (KSP) algorithm can effectively process the multi-link topology among the nodes, and has low understanding complexity and higher implementing efficiency.