Embodiments of the present invention relate to a virtual machine integration technology, and in particular, to a method, an apparatus, and a system for virtual cluster integration. The method includes: performing a calculation through a search algorithm to obtain the minimum number of physical machines which are capable of accommodating all virtual machines in a virtual cluster, and obtaining all virtual integration solutions satisfying the minimum number of physical machines; then calculating CPU voltage consumption of each virtual integration solution, and selecting a solution with lowest CPU voltage consumption from these virtual integration solutions; and formulating a virtual integration migration policy according to the virtual integration solution with the lowest CPU voltage consumption. Therefore, through the embodiments of the present invention, a virtual integration solution with lower CPU voltage energy consumption can be obtained, thereby greatly improving an energy saving and emission reduction effect of a virtual cluster integration solution.