The invention discloses a distributed calculating method, and a management device and system. The distributed calculating method includes: receiving a request, associated with a distributed calculation task, from a user; determining more than one limited virtual machines for performing the distributed calculation task according to virtual resource state information of limited virtual machines in a limited virtual machine cluster while the request is received; allocating the distributed calculation task to the more than one limited virtual machines so as to allow the more than one limited virtual machine to perform calculation corresponding to the distributed calculation task; and outputting the calculation result acquired through calculation of the more than one limited virtual machines to the user. The distributed calculation method and the management device and system can fully utilize idle virtual resources of a physical machine cluster so as to balance the resources of the physical machine cluster, and then improve the utilization rate of resources.