The invention discloses a resource reconstruction method based on service remaining time sequencing in an elastic exchange network, relating to the field of elastic exchange networks. According to the method, service transmission time is taken as a parameter for encapsulating into each frequency slot occupied by a service of which the needed transmission time can be estimated with a computer when the service is transmitted and resources are distributed to the service. When services of this type are transmitted in the network and spectral reconstruction of network resources is needed, the services are arranged from the left end to the right end of a frequency spectrum according to a service remaining time sequencing way, and released frequency slot resources can construct continuous frequency spectrum resources along with the continuation of time when the frequency slot occupation time of the services is reduced to zero along with the continuation of time, so that maximum continuation of idle frequency slots is realized, frequency spectrum fragments are reduced, the spectral reconstruction times are reduced, and the service blocking rate is reduced.