A method for realizing secure communication between machine type communication devices, comprising: receiving, by a network entity, a direct communication request from a directly-communicating MTC device, wherein the direct communication request contains information of the directly-communicating MTC device and information of another MTC device with which the directly-communicating MTC device needs to directly communicate; wherein the directly-communicating MTC device and the another MTC device are part of an established MTC group; creating, by the network entity, an MTC device group for the directly-communicating MTC device, and saving MTC device group information corresponding to the created MTC device group and MTC device information of MTC devices contained in the created MTC device group which consists of the MTC devices needing to directly communicate, wherein the MTC device group information comprises MTC device group identification information and MTC device group key information; wherein an MTC device group key is used as a shared key between different MTC devices in the created MTC device group and is used for protecting secure communication between the different MTC devices in the created MTC device group; the method further comprising: generating, by the network entity, an encryption key on basis of the MTC device group key information, and the MTC device group information further comprises the encryption key; and sending, by the network entity, the MTC device group information of the created MTC device group to all MTC devices contained in the created MTC device group, which then establish a secure connection for direct communication using the encryption key contained in the MTC device group information. receiving, by a network entity, a direct communication request from a directly-communicating MTC device, wherein the direct communication request contains information of the directly-communicating MTC device and information of another MTC device with which the directly-communicating MTC device needs to directly communicate; wherein the directly-communicating MTC device and the another MTC device are part of an established MTC group; creating, by the network entity, an MTC device group for the directly-communicating MTC device, and saving MTC device group information corresponding to the created MTC device group and MTC device information of MTC devices contained in the created MTC device group which consists of the MTC devices needing to directly communicate, wherein the MTC device group information comprises MTC device group identification information and MTC device group key information; wherein an MTC device group key is used as a shared key between different MTC devices in the created MTC device group and is used for protecting secure communication between the different MTC devices in the created MTC device group; the method further comprising: generating, by the network entity, an encryption key on basis of the MTC device group key information, and the MTC device group information further comprises the encryption key; and sending, by the network entity, the MTC device group information of the created MTC device group to all MTC devices contained in the created MTC device group, which then establish a secure connection for direct communication using the encryption key contained in the MTC device group information. generating, by the network entity, an encryption key on basis of the MTC device group key information, and the MTC device group information further comprises the encryption key; and sending, by the network entity, the MTC device group information of the created MTC device group to all MTC devices contained in the created MTC device group, which then establish a secure connection for direct communication using the encryption key contained in the MTC device group information.