1. A resource management method in a computer system, wherein the computer system comprises a physical device platform executing a virtual resource management, the physical device platform comprises at least one physical machine, the virtual resource management platform creates a virtual machine cluster; and the method comprises: obtaining, by the computer system, a resource average utilization rate constraint parameter of the virtual machine cluster; obtaining, by the computer system, a statistical value of a current resource average utilization rate of the virtual machine cluster; and comparing, by the computer system, the statistical value of the current resource average utilization rate of the virtual machine cluster with the resource average utilization rate constraint parameter of the virtual machine cluster; when the statistical value of the current resource average utilization rate of the virtual machine cluster is smaller than the resource average utilization rate constraint parameter of the virtual machine cluster by a difference less than a set tolerance threshold, determining, by the computer system, that it is about to start performing physical resource scheduling of capacity expansion or adding of a new virtual machine on the virtual machine cluster, suppressing, by the computer system, a physical machine capacity deduction operation on the physical device platform.