The PCI Express protocol is a high-speed serial bus protocol. The transaction layer is an important part of the entire protocol. In the real-time transmission of mass data
the system structure of the protocol transaction layer is designed in this paper. The main functions are:to achieve the affairs of the data transmission
data reception and credit flow control
as well as the logic design of the application layer interface and data link layer interface. These features are implemented in Verilog HDL language and simulated by Modelsim. The simulation of the transaction layer system verifies the correctness of the design.