The disclosure provides a method for improving a service restoration speed in a transmission network, comprising: in a service set-up process, the PCE receives a route computation request including restoration attributes and constraint conditions from a Path Computation Client (PCC), and computes and saves the restoration routes available for the service according to the constraint conditions; and, when receiving the restoration route computation request for the service from the PCC, the PCE selects a route from the restoration routes locally saved and available for the service according to the selection conditions included in the restoration route computation request and sends it to the PCC which restores the service by the received route. The disclosure further provides a PCE.