The present disclosure is applicable to the field of device energy-saving control, and provides a dynamic energy-saving method and apparatus for a PCIE device, and a communication system thereof. The method includes: obtaining a system energy-saving policy; and using a PCIE energy-saving module to control a PCIE device and a PCIE link to enter a corresponding linkage energy-saving state according to the obtained system energy-saving policy. In the present disclosure, a “D” state of a PCIE device is associated with an “L” state of a link into a new linkage energy-saving state, and the device and the link are controlled to enter the corresponding linkage energy-saving state according to a preset energy-saving policy, thereby improving energy-saving efficiency.