Abstract: The present application provides a method for dynamically allocating resources in an SDN/NFV network based on load balancing. For multimedia services with different demands, a virtual link mapping target, a constraint and a load state of a physical link are associated. A subtask is adaptively mapped to a network node according to the load state of the physical link. The method effectively distinguishes used resources and remaining resources of a physical node and a link to balance the load, and thereby improve the utilization of network resources and avoid occurrence of a local optimum or current optimum. The solution involves performing a subtask mapping to find a server node satisfying constraints for each subtask in a service request. The model for mapping the subtask is min T ? V ? ? Target 1 s . t . ? C 1 , C 2 , C 3 , C 4 .