Abstract: Blockchain system is rapidly integrated into the various kinds of technology, and the affection from underlying network topology structure the performance of block chain is very limited. This paper presents a spectrum partitioning method based on symbol variation. The importance of each network node to the whole blockchain was studied. We selected the critical evaluation of nodes according to the different criticality index. We used simulation experiment to investigate after remove the node performance degradation and it was concluded that the key of the node was one of the largest nodes, resulting in a decline in performance. At the same time with the existing in the middle of the centricity, degree of tight centricity and centricity key indicators such as comparison, we found that when to remove these key nodes, the block chain performance reduced faster. Therefore, this paper concludes that the proposed method is superior to the existing three methods, thus maintaining the security and stability of the blockchain.