The invention provides a link load control method and a stacking device, which solve the problem that stacked data messages in remote stacking of a cross-IP (Internet Protocol) network are lost due to network congestion. The link load control method is applied to data transmission of an annular link which is composed of at least three stacking devices through the IP network connection; in the annular link, the shortest path for transmitting data generated by the current stacking device to a target stacking device is regarded as a main path while the other path is regarded as a standby path. The link load control method comprises the steps of: determining the congestion condition of a transmitting link from the current stacking device to an adjacent stacking device based on a packet transmitting speed of a stacking port of the current stacking device and a packet receiving speed of a stacking port of the adjacent stacking device; when the transmitting link is determined to be congested, transmitting the data including the data to be transmitted in the main path of the transmitting link through the standby path corresponding to the main path by the current stacking device.