The invention discloses an all-path detection method, device and system in order to adapt to path connectivity detection on a service chain in an SF (Service Function) load balancing mode. The methodincludes the following step: a controller generates a change factor for each SF, and sends the change factor corresponding to each SF to an SFF (Service Function Forwarder) corresponding to the SF, wherein the change factor is used to generate a message number; the controller sends a detection message carrying an initial message number to a first-hop SFF in a service chain so the first-hop SFF cangenerate a new message number based on the initial message number and the change factor corresponding to the local SF of the first-hop SFF, add the new message number to the detection message and forward the detection message carrying the new message number to the local SF to complete the forwarding of the detection message; and the controller receives a reported detection message carrying a target message number, and gets a forwarding path of the detection message based on the target message number and a preset rule to complete all-path detection. Thus, all-path detection in a service chainscenario can be realized.