The invention provides a mail group creation method and device. The method can comprise the steps that a server detects a mail group creation requirement for an instant messaging group; according to the members included in the instant messaging group, the server extracts the mail address corresponding to each member; the server gathers the mail addresses corresponding to all members in the instant messaging group and generates a corresponding mail group; and when the mail group is considered as an addressee of the mail, the mail is sent to each mail address in the mail group. Through adoption of the method, the mail group can be created automatically, and the method can help to simplify user operation.