The invention discloses a virtual machine processor resource adjusting method and device and a virtual machine system. The method comprises, for a VCPU (virtual central processor unit) to be deleted of a virtual machine (VM), identifying whether the VCPU contains a resource scheduling request; responding to the resource scheduling request of the VCPU, according to the response time threshold value of the operating system of the VM for starting automatic fault detecting operation, delaying the response to the resource scheduling request, and enabling the resource scheduling request to obtain response within the response time threshold value; performing response when the resource scheduling request does not obtain the response within the response time threshold value, starting the automatic fault detecting operation through the operating system of the VM, scheduling queued processes in the VCPU to other VCPUs of the VM; deleting the VCPU, and releasing physical server CPU (central processor unit) resources occupied by the VCPU. The virtual machine processor resource adjusting method can reduce VCPU resources in an operating state and achieve flexible expansion and retraction of virtual machine resources.