The flow scheduling on cloud data center network is a hotspot at present. More practical flow scheduling assume that the flow information is unknown in advance, but the performance of these scheduling scheme is not good enough. By combining the multi-level feedback queue with the per-flow scheduling, this paper designs a multiple level scheduling scheme FISH based on the flow isolation, which solves the queueing competition of different flows. Experimental results show that the proposed scheme has stable performance and reduces the completion time of small flows by up to 8.6%.