Bancor is a system that provides liquidity for small market value tokens. It has one or more erc20 tokens that can be traded as reserves. New tokens are issued through smart contracts in exchange for reserve tokens. The price of new tokens is self pricing through smart contracts, so that they can be directly converted between tokens without exchanges, and there is no need for a second party to participate in transactions or a third party to make deals. The network effect of tokens created by Bancor protocol reduces the barriers to market entry for these new currencies and effectively solves the liquidity problem. The new currency is endorsed by Bancor, which is endorsed by eth, and Bancor's constant reserve ratio (CRR) is set and maintained at 20%. BNT is issued by sending eth to the smart contract in which Bancor holds reserves. These eth sent in the past become Bancor's endorsement. Under such a setting, the user can send 20eth to the smart contract to purchase 100bnt, and the 20eth will be forcibly collected into the reserve by the smart contract. In the same way, BNT can be redeemed back to eth. As long as users send it to Bancor's smart contract, they will get some eth. Bancor protocol allows users to generate or destroy BNT every time they deposit or withdraw reserve (ETH). If the price of eth rises (due to the development of Ethereum Ecology), the price of BNT will also rise (because BNT and its reserve token eth maintain a constant reserve ratio), and the rise of BNT price will also increase the price of new currency. The biggest innovation of Bancor protocol is that the value discovery of digital currency in traditional exchanges is based on the real-time synchronous matching of bid and ask. However, based on Bancor protocol, the price of digital currency depends on the balance of reserves and the circulation of tokens, and the process of value discovery is asynchronous.