Billing server, tax copying system and tax copying method

The invention provides a billing server, which is provided with a peripheral component interconnect (PCI) bus, a first processor, a security module, a network interface and a data processing device connected with the PCT bus respectively; enterprise information and a key are stored in the security module, and the security module provides encryption and decryption programs, generates tax control codes corresponding to bills by using the key and the encryption algorithm, encrypts the bill data information and generates bill data cipher texts; the network interface provides a connecting interface of the billing server and a billing terminal; and the data processing device stores and searches the bill data cipher texts. The invention also provides a tax copying system, which consists of the billing server, at least one billing terminal, at least one tax copying storage device, and a local area network for connecting the billing server and the billing terminal; and the tax copying storage device can be connected with the billing terminal, or connected with the billing server, or connected with the data processing device in the billing server.