The previous cashier system in the shop is the use of a Windows system. However, the Windows system needs to be equipped with hardware that can run Windows, so the cost is very high, and the cash register system uses very limited software. So the customer wants to develop an Android-based POS machine. The client offered detailed hardware information, such as what interfaces and dimensions should be around. We designed the development board then based on the hardware characteristics of the development board, we carried out the configuration of the Android system. We downloaded the Android OS source code based on Rock Chip from the repo. At first, the source code was as high as 22G. Later, we removed most of the source code and only left about 10G. The source code build of the Android system needs to be built on the Ubuntu system. It takes about 6 to 10 hours to build a complete source code. In the end, we can get the Android system to run smoothly on the motherboard we designed.