As the information society enters the Internet of things era, all devices need to develop applications and drivers for comput- er systems to identify and use. This paper introduces the process of developing the underlying device driver under the Ubuntu 16.04 system kernel. Based on the Ubuntu system kernel, source tree construction, the driver module compiling, loading and unloading are completed. It analyzes the design method of character device driver in Ubuntu system. Finally, the character device driver designing is successful verified through Ubuntu system.