Method for intercepting mistakenly sent message and instant messaging system

The invention discloses a method for intercepting a mistakenly sent message. The method is characterized in that the method comprises the following steps: setting a message input sensitive word interception rule of a certain group or individual in a certain client; setting a message input state of a certain group or individual in the client as a sensitive statement interception state; setting a unique identification code of the group or the individual, and synchronizing the set unique identification code of the group or the individual, an interception rule and a message input state thereof toa server by the client; if sensitive statement input to a certain group or personal message is triggered in the client, enabling the client to perform first interception on related messages; when theclient is reset, resetting the client; and enabling the server to synchronize the interception state and rule of the group or personal sensitive statement stored in the server to the client side, andwhen the client side does n