In terms of high-speed data transmission, PCI Express interface is undoubtedly a better choice. PCIe is widely used in data centers and servers, more and more large-scale SoC chips are also based on PCIe interface, such as GPU and DPU. However, with the continuous improvement of PCIe transmission rate, the PCIe protocol has become increasingly complex, which brings great challenges to both design and verification.For PCIe Gen5, there are multiple types of PCIe devices on the server, including RC, EP, Switch, and Retimer. Meanwhile, CXL type 3 memory expansion devices are also gradually being adopted, which is based on PCIe Gen5. This means that DV engineers of PCIe IP vendor need to develop a large number of test vectors to ensure coverage.From the perspective of delivering mature products, software/firmware development and verification for PCIe/CXL devices are equally important compared to RTL in pre-silicon process. Traditional DV methods are difficult to ensure software and hardware system level verification on Gen5 speed.For the above PCIe/CXL verification challenges, under the help of Cadence tools, INNOSILICON have developed advanced and efficient solutions that can meet with the sign off standard. This solution mainly includes four parts: Triple-Check Simulation, Qemu Co-Sim, Z1 EMU, and FPGA prototype verification. The Cadence PCIe VIP and Triple-Check test vectors can save a lot of testcase development work while ensuring high coverage of basic functions. With the help of Cadence Palladium Z1 and FPGA, The completeness of software firmware development and system verification can be achieved. Z1 and FPGA have different advantages and cannot completely replace each other. At the same time, QEMU Co-sim as a new INNOSILICON self developed verification method, can let us run system level PCIe verification without hardware restrictions.This solution can cover the verification of all different types of PCIe devices, including CXL type3 device. This paper will provide a detailed introduction based on different typical cases.