For a cloud data center， minimizing resource wastage and increasing resource utility efficiency are two important aims. So an efficient virtual machine allocation strategy is necessary. A flower pollination algorithm based virtual machine allocation（FPA-VMA）approach is proposed. In FPA-VMA， the plant has only one flower， and each flower produces only one pollen gamete. The flower and pollen gamete are similar to the virtual machine and physical machine in cloud data center. The cloud client resource requesting model and the multi-dimensional resource energy consumption model are also analyzed and described. FPA-VMA uses a strategy which is called dynamic switching probability （DSP）. DSP finds a near optimal solution quickly and balances the exploration of the global search and exploitation of the local search， thus improving the global convergence of FPA-VMA. Experimental results on the real virtual machine workloads show that FPA-VMA has better performance in resource wastage and energy consumption compared with previous VMA strategies.