The invention relates to a resource allocating method and device. The resource allocating method comprises the following steps of: providing options to a service application through a basic facility management node, and determining physical resources of a grade corresponding to the result according to selection results of the options fed back by the service application, establishing virtual resources on the physical resources corresponding to the results, and providing the virtual resources to the service application. Correspondingly, the invention provides the basic facility management node so as to meet the allocation requirements on the service application and ensure the QoS (quality of service) of the service application.