A notification method for releasing a context of a terminal, performed by a first network node, the method comprising: sending (102, 202), by the first network node, a first notification to a second network node or a second communication system when a terminal finds the second network node currently serving the terminal cannot meet a requirement of the terminal and therefor switches from accessing the second network node to accessing the first network node or when the terminal switches from accessing the second communication system to accessing a first communication system; wherein the first notification is at least used for notifying the second communication system or the second network node to release the context of the terminal; and when the terminal switches from accessing the second network node to accessing the first network node or when the terminal switches from accessing the second communication system to accessing the first communication system, the method further comprises: acquiring identification information of the second communication system or the second network node reported by the terminal (101, 201); wherein sending (102, 202), by the first network node, the first notification is based on an acquired second notification sent by the terminal, the second notification is used for indicating the first network node to send the first notification to the second communication system or the second network node (101, 201); wherein the second notification further comprises a cause value, wherein the cause value is used for indicating a reason for triggering the first network node to send the first notification to the second communication system or the second network node, characterized in that the first notification further comprises identification information of the terminal, the identification information of the terminal comprises International Mobile Subscriber Identity, IMSI, or International Mobile Equipment Identity, IMEI; and the cause value comprised in the second notification is used for indicating to the first network the reason that the terminal has left the second network node. sending (102, 202), by the first network node, a first notification to a second network node or a second communication system when a terminal finds the second network node currently serving the terminal cannot meet a requirement of the terminal and therefor switches from accessing the second network node to accessing the first network node or when the terminal switches from accessing the second communication system to accessing a first communication system; wherein the first notification is at least used for notifying the second communication system or the second network node to release the context of the terminal; and when the terminal switches from accessing the second network node to accessing the first network node or when the terminal switches from accessing the second communication system to accessing the first communication system, the method further comprises: acquiring identification information of the second communication system or the second network node reported by the terminal (101, 201); wherein sending (102, 202), by the first network node, the first notification is based on an acquired second notification sent by the terminal, the second notification is used for indicating the first network node to send the first notification to the second communication system or the second network node (101, 201); wherein the second notification further comprises a cause value, wherein the cause value is used for indicating a reason for triggering the first network node to send the first notification to the second communication system or the second network node, characterized in that the first notification further comprises identification information of the terminal, the identification information of the terminal comprises International Mobile Subscriber Identity, IMSI, or International Mobile Equipment Identity, IMEI; and the cause value comprised in the second notification is used for indicating to the first network the reason that the terminal has left the second network node. acquiring identification information of the second communication system or the second network node reported by the terminal (101, 201); wherein sending (102, 202), by the first network node, the first notification is based on an acquired second notification sent by the terminal, the second notification is used for indicating the first network node to send the first notification to the second communication system or the second network node (101, 201); wherein the second notification further comprises a cause value, wherein the cause value is used for indicating a reason for triggering the first network node to send the first notification to the second communication system or the second network node, characterized in that the first notification further comprises identification information of the terminal, the identification information of the terminal comprises International Mobile Subscriber Identity, IMSI, or International Mobile Equipment Identity, IMEI; and the cause value comprised in the second notification is used for indicating to the first network the reason that the terminal has left the second network node.