Embodiments of the present invention disclose a method, an apparatus and a system for joint optimization. The method for joint optimization includes: decomposing the joint optimization of an entire network into the joint optimization performed in each sub-network, regarding a bandwidth requirement for a server off the sub-network as a bandwidth requirement for a virtual server on a port, iteratively performing the joint optimization in each sub-network, and applying results of the joint optimization in the network. In the embodiments of the present invention, the bandwidth requirement for the server off the sub-network is regarded as the bandwidth requirement for the virtual server on the port, the joint optimization is iteratively performed in each sub-network, and the results of the joint optimization are applied in the network, so that the joint optimization of the entire network is performed in parallel.