The invention relates to a dynamic deployment method for virtual machines. The method comprises the following steps: dividing residual resources of each dimension on a physical machine by demanded resource quantity of a corresponding dimension of a to-be-deployed physical machine so as to obtain a ratio sequence, screening out the minimum value of ratios in the sequence and taking the minimum value as the maximum accommodating number of the physical machine to a to-be-deployed virtual machine; selecting a physical machine with the largest maximum accommodating number, and judging whether the physical machine has enough resources to accommodate the to-be-deployed virtual machine; if the value of the maximum accommodating number of the target physical machine is greater than or equal to 1, deploying the virtual machine to the physical machine; and if the maximum accommodating number of the target physical machine is less than 1, outputting that the deployment of the virtual machine fails. By using the method disclosed by the invention, a 'short board' phenomenon, namely, resources of other dimensions are wasted because of the lack of resources of some dimension of a physical machine in a cluster, can be avoided, and the resource utilization ratio of the physical machine can be increased.