A fault detection method of LACP packet timeout provided including: receiving a LACP packet from a target port of the partner device through a local port, the LACP packet at least includes a phase identifier to indicate a negotiation phase of a LACP negotiation process between the target port and the local port; sending a response LACP packet corresponding to the LACP packet to the target port through the local port; generating a LACP service processing entry for the LACP packet to indicate a LACP service processing phase performed by the actor device for the LACP packet; in response to that no LACP packet from the target port being received through the local port continues for a preset waiting time, performing fault detection based on the phase identifier and the LACP service processing entry so to obtain fault cause information to indicate a LACP packet timeout of the target port.