A service chain fault detection method, wherein the service chain is a set of service function nodes, included in the service chain that a packet passes through according to an order of the service function nodes, wherein the method comprises: obtaining, by a service forwarding entity, SFE, a first fault tracing detection request packet, and then determining to communicate with a first service function, SF, node, wherein the first fault tracing detection request packet comprises a path identifier, ID, and an address of a device for initiating fault detection, and the path ID is used to identify a path of a service chain; obtaining, by the SFE, an ID of the first SF node; and sending, by the SFE, a first fault tracing detection response packet to the device for initiating fault detection, wherein the first fault tracing detection response packet comprises the path ID, the ID of the first SF node, and the address of the device for initiating fault detection; characterised in that the determining, by an SFE, to communicate with a first SF node on the service chain comprises: determining, by the SFE according to the path ID, to forward the first fault tracing detection request packet according to a first forwarding entry, wherein the first forwarding entry comprises the path ID and an address of the first SF node; sending, by the SFE, the first fault tracing detection request packet to the first SF node according to the address of the first SF node; and receiving, by the SFE, a second fault tracing detection request packet from the first SF node, wherein the second fault tracing detection request packet comprises the path ID and the address of the device for initiating fault detection. obtaining, by a service forwarding entity, SFE, a first fault tracing detection request packet, and then determining to communicate with a first service function, SF, node, wherein the first fault tracing detection request packet comprises a path identifier, ID, and an address of a device for initiating fault detection, and the path ID is used to identify a path of a service chain; obtaining, by the SFE, an ID of the first SF node; and sending, by the SFE, a first fault tracing detection response packet to the device for initiating fault detection, wherein the first fault tracing detection response packet comprises the path ID, the ID of the first SF node, and the address of the device for initiating fault detection; characterised in that the determining, by an SFE, to communicate with a first SF node on the service chain comprises: determining, by the SFE according to the path ID, to forward the first fault tracing detection request packet according to a first forwarding entry, wherein the first forwarding entry comprises the path ID and an address of the first SF node; sending, by the SFE, the first fault tracing detection request packet to the first SF node according to the address of the first SF node; and receiving, by the SFE, a second fault tracing detection request packet from the first SF node, wherein the second fault tracing detection request packet comprises the path ID and the address of the device for initiating fault detection. determining, by the SFE according to the path ID, to forward the first fault tracing detection request packet according to a first forwarding entry, wherein the first forwarding entry comprises the path ID and an address of the first SF node; sending, by the SFE, the first fault tracing detection request packet to the first SF node according to the address of the first SF node; and receiving, by the SFE, a second fault tracing detection request packet from the first SF node, wherein the second fault tracing detection request packet comprises the path ID and the address of the device for initiating fault detection.