In order to solve the problem of office automation, this paper proposes the design and implementation of office automation system based on Internet of things technology. This method is to carry out mobile office function through smart phones to realize business message exchange and real-time processing of process approval business. The system adopts b/s structure and adopts the form of front-end machine to realize information sharing between the mobile system and the original system. When users choose to send mail or reply to mail, the client can read the current user name as the sender by itself. The number of uploaded attachments is limited to three at most, and the total size of attachments is not greater than 100 m. Conclusion. This method effectively improves the work efficiency of employees.