The invention discloses an Android upper layer client and STM32 bottom layer communication method. Through FTDI USB to R232, miniature USB data information of a tablet computer can be converted into general serial port information of RS232. An Android upper layer client converts a data information format into an RS232 data information format through the FTDI USB to RS232. RS232 serial port information is finally converted into TTL information through an RS232 level conversion TTL level module and then is received by a bottom layer STM32. On the contrary, a process that the STM32 transmits information to the Android upper layer is an opposite conversion process. By using the method of the invention, a technical problem that the Android upper layer client can not communicate with the bottom layer STM32 directly through a serial port is solved.