The present invention provides a path computation method, a Path Computation Element (PCE), a node device, and a network system. The method includes: receiving a path computation request message (S201), where the path computation request message carries a network type identifier and traffic parameter constraint conditions of a path required to be computed, and the network type identifier indicates a type of a network where the path required to be computed locates; determining the network through the network type identifier, and computing the path in the network according to the traffic parameter constraint conditions (S202); and sending a path computation response message (S203), where the path computation response message carries the computed path. The problem of distinguishing and computing Traffic Engineer (TE) paths for various types of services in a multi-region convergence network is solved.