A system and method for managing a network by value-based estimation is provided. A network device requesting communication is defined as an active point and a network device receiving a request for communication is defined as a passive point. A value of a network device is determined according to the number of active points connected to the corresponding network device, and a value of a network device that is in a path of communication between network devices is determined based on a value of a network device passing through the corresponding network device. When a policy for changing a network environment is transferred in a state where the values of the network devices have been estimated, a policy conflict test is performed on the basis of the estimated values of the network devices, thereby determining application of the policy in due consideration of the values and significance of the network devices.