This study proposes an innovative technology of Virtual COM Port Driver applied to the SaaS cloud manufacturing system, so that user can only via a web browser to complete all operations of system. Flexibility of the system extensions, and support manufacturing enterprise use other communications equipment at work, for example RFID products, GPS receiver. Information integration, solve each computer to be fitted Middleware to read native components and retrieve information for the inconvenience. This study proposes five-layer model of cloud manufacturing system, and through the virtualization web server to achieve cloud infrastructure layer. In particular, the Virtual Com Port Driver is deployed in the cloud infrastructure layer and middleware layer, and the signal device layer can communicate directly to the cloud infrastructure layer via the web browser. Through a case study, to implement the Virtual COM Port Driver technology to verify the cloud server can capture the local COM port successfully only via the web browser and integrate the information further.