Method and apparatus for ensuring data consistency between local area networks

The embodiments of the present invention provide a method and apparatus for ensuring data consistency between local area networks including a first local area network and a second local area network isolated from an external network, where the first local area network comprises therein a first device that has an authority for sending an email to the external network; the second local area network comprises therein a second device that has an authority for receiving an email from the external network and a server that has an authority for receiving data from the external network; and the method comprises: acquiring specific data in the first device; uploading the specific data to the server; generating a specific email according to the specific data; and sending the specific email to the second device. The method and device in the embodiments of the present invention are used for synchronizing data between the local area networks.