Embodiments of the present invention disclose a method, apparatus, and system for detecting performance of a layer 3 virtual private network. A first node creates an OAM instance according to OAM configuration information set by a user, and sends the OAM configuration information to a second nodet; the second node creates an OAM instance according to the OAM configuration information; and the first node performs OAM detection by sending an OAM packet to the second node and/or receiving an OAM packet from the second node, where the sending and/or receiving is implemented by using the OAM instance of the first node. According to the present invention, not only an OAM configuration procedure is simplified and manpower is saved, but also consistency of OAM configuration at two ends can be ensured. In addition, a configuration delay in this dynamic configuration manner may be ignored.