The software of the regular medication reminder device includes a PC program and an MCU program. The PC program runs on the PC. The MCU program runs on the single chip microcomputer. The MCU program was developed in C51 language and debugged under Keil uvision4. It is composed of a main program, timer interrupt service program, communication interrupt service program and a key interrupt service program. The main program will complete the system initialisation and make the system enter low power state in spare time.