Fast Bitcoin (FBTC for short) has successfully forked at block height 501225 of Bitcoin (BTC) (14:55:44, December 27, 2017, Hong Kong time). On the issue of capacity expansion, FBTC has great innovations. FBTC assigns the blockchain capacity to the miners for adjustment, the minimum is 1M, and the maximum is 10M. Miners need to vote for each block, and adjust the block capacity limit at the same time when the difficulty is adjusted. On the issue of transaction efficiency, FBTC uses the account model to replace the inefficiency and redundancy of UTXO, and adopts a hard fork in the implementation method to solve the problem at one time. FBTC adopts the DPOS consensus mechanism, which greatly reduces the energy consumption of POW, while the total amount of currency does not increase.