1. A resource management method in a communication system, comprising: judging whether an operating status variation of the communication system affects resource management information of the communication system, and if yes, re-collecting the resource management information, wherein the resource management information comprises information regarding statuses of nodes, interference statuses between links and traffic flows in the communication system; and determining a resource allocation policy for the communication system according to the resource management information, wherein the communication system comprises a primary system network and at least one secondary system network, the primary system network and the at least one secondary system network have different priority levels, the resource management information comprises information regarding statuses of nodes, interference statuses between links and traffic flows in the primary system network and the at least one secondary system network, the resource allocation policy is determined according to the resource management information and a resource allocation target, the step of determining the resource allocation policy for the communication system according to the resource management information comprises: establishing a quantized relation between the resource management information and the resource allocation target; and determining the resource allocation policy according to the established quantized relation, the step of establishing the quantized relation between the resource management information and the resource allocation target comprises: establishing a resource allocation model according to the resource management information, wherein the resource allocation model reflects neighborhood relations between the links, mutual exclusion relations between the links, and a bandwidth requirement and a priority level of each link in the communication system; and establishing a constrained condition for resource allocation and quantizing the resource allocation target according to the resource allocation model, and the step of determining the resource allocation policy according to the established quantized relation comprises: arranging an order for links in the resource allocation model, and selecting links that can be allocated with resources simultaneously therein; and allocating resources for each of the selected links according to the constrained condition for resource allocation and the quantized resource allocation target.