The present invention provides an optimization method and system for minimizing network energy consumption based on traffic grooming. The method includes: generating a set of service requests in an elastic optical network, and calculating a reachable node set of shortest paths from source to destination nodes for each service request; establishing a virtual reachable path in the reachable node set of shortest paths; and establishing a target function of an integer linear programming model of the minimizing network energy consumption, and sequentially determining whether a bandwidth capacity constraint of a single spectrum slot, a path uniqueness constraint, a spectrum allocation constraint, and an optical regenerator quantity constraint are satisfied, where if all constraints are satisfied, the service request is successfully established, or if any of the constraints is not satisfied, the service request fails to be established. The present invention helps to improve the energy efficiency of service requests.