A method for establishing an interface between, virtualized network function managers, VNFMs, comprising: receiving, by a first VNFM, an interface establishment request message sent by a second VNFM, wherein the interface establishment request message is used to request to establish a communication interface between the first VNFM and the second VNFM; determining, by the first VNFM according to the interface establishment request message and an interface establishment policy of the first VNFM, whether to allow establishment of the communication interface, wherein the interface establishment policy of the first VNFM is stored in a memory of the first VNFM; and when the first VNFM determines to allow establishment of the communication interface, sending, by the first VNFM, an interface establishment response message to the second VNFM, wherein the interface establishment response message is used to indicate that the communication interface is successfully established; wherein the interface establishment policy of the first VNFM comprises a maximum quantity of communication interfaces that are allowed by the first VNFM to be established; and the determining, by the first VNFM according to the interface establishment request message and an interface establishment policy of the first VNFM, whether to allow establishment of the communication interface comprises: determining, by the first VNFM according to the interface establishment request message, whether a quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; and determining, by the first VNFM, to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; or determining, by the first VNFM, not to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is equal to the maximum quantity of communication interfaces that are allowed by the first VNFM to be established. receiving, by a first VNFM, an interface establishment request message sent by a second VNFM, wherein the interface establishment request message is used to request to establish a communication interface between the first VNFM and the second VNFM; determining, by the first VNFM according to the interface establishment request message and an interface establishment policy of the first VNFM, whether to allow establishment of the communication interface, wherein the interface establishment policy of the first VNFM is stored in a memory of the first VNFM; and when the first VNFM determines to allow establishment of the communication interface, sending, by the first VNFM, an interface establishment response message to the second VNFM, wherein the interface establishment response message is used to indicate that the communication interface is successfully established; wherein the interface establishment policy of the first VNFM comprises a maximum quantity of communication interfaces that are allowed by the first VNFM to be established; and the determining, by the first VNFM according to the interface establishment request message and an interface establishment policy of the first VNFM, whether to allow establishment of the communication interface comprises: determining, by the first VNFM according to the interface establishment request message, whether a quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; and determining, by the first VNFM, to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; or determining, by the first VNFM, not to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is equal to the maximum quantity of communication interfaces that are allowed by the first VNFM to be established. determining, by the first VNFM according to the interface establishment request message, whether a quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; and determining, by the first VNFM, to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is less than the maximum quantity of communication interfaces that are allowed by the first VNFM to be established; or determining, by the first VNFM, not to allow establishment of the communication interface, when the quantity of established communication interfaces of the first VNFM is equal to the maximum quantity of communication interfaces that are allowed by the first VNFM to be established.