Abstract: Mobile power supply will be applied more and more widely with the use of intelligent mobile phone,tablet computer,PDA.Design method of portable power source composed of DC/DC converter,lithium battery protection circuit and single chip microcontroller is put forward.The schematic circuit is proposed,the software design process and the device parameters selection are described.The project which covers the electronic technology,computer technology and EDA technology is very suitable to be used as an experiment topic oriented innovative experiment project.