Disclosed are a CPK-based digital bank, a digital currency and a payment method. The digital currency is a core component of the digital bank. The digital currency is realized by means of a CPK digital signature, and a payer provides an account authenticity certification, an amount authenticity certification and a fund allocation authenticity certification, thereby effectively preventing crimes inside or outside a bank. The digital currency directly takes an account identifier as an account number. The digital currency can be used in on-line operations, as well as off-line operations, thereby satisfying face-to-face trade requirements between a great number of retail accounts. The CPK digital bank is realized by means of a CPK chip without support of other devices, such that everyone can check the authenticity of the digital currency.