Because its data structure creates a digital transaction ledger, block-chain will build a more transparent and publicly verifiable system that will fundamentally change the way of our transaction activities, asset value, contract performance, and sharing data across industries. Since 2015, “block-chain” has become the hottest topic to the world’s major financial giants. This paper first introduces the principle and characteristics of block-chain technology. The block-chain technology based on encryption algorithms builds a global distributed secure network database that records and updates transaction information through decentralized chain connections and block chronological arrangement. Secondly, it focuses on the technological innovation of block-chain in financial systems. Block-chain technology solves the problems of decentralization, information security, and information disclosure in financial transactions. Thirdly, we put the emphasis on the block-chain technology application prospect in the field of finance. The block-chain technology will be used in digital currency, payment and clearing, smart contracts, as well as financial transactions. At last, we lead a warning that the application of block-chain technology could bring financial risks, which includes a technical problem, resource problem, and competition problem. Our conclusion is that block-chain will change the credit management mode of the traditional financial system. But due to the shortcomings of technical maturity, resources reserve, and the regulation of competition, the application value of block-chain in financial field will face risk. Therefore, monetary authorities should reserve talents and technologies of block-chain, and strengthen the basic research, practical application and standardization research of block-chain. According to the domestic and international situation, the authorities should issue legal digital currency, build internationally competitive Chinese block-chain products, and continuously explore effective regulatory model block-chain to secure a healthy and sustainable development of the chain block industry.