Error information acquisition method and network management device

The invention discloses an error information acquisition method and a network management device used to solve a technical problem that it is complex to accurately determine the command-executing failure cause of a proxy device. The method includes steps that a network management device sends a first command to the proxy device, wherein the first command includes a first ID for uniquely identifying the serial number of the first command; the network management device determines, according to a first response message obtained from the proxy device, whether or not the proxy device successfully executes the first command, and the network management device sends a second command to the proxy device if not, wherein the second command is used for instructing the proxy device to send, to the network management device, a first error information indicating that the proxy device fails to execute the first command, and the proxy device stores an error information table including the IDs and first error information corresponding to the IDs; and the network management device receives a second response message sent by the proxy device and corresponding to the second command, wherein the second response message includes the first error information.