Abstract This design introduces a warning system of intelligent alarm device based on the automotive,this design is composed of ultrasound module,the signal receiving module,single-chip microcomputer processing module,digital di- splay module and the acousto-optic alarm module components.It is control- ed by the single-chip intelligent microcontroller and it can automatically detect obstacles in car driving and the back-draft driving process.Then it can also measure the distance between cars and obstacles through the ultrasonic ranging principle and it will display the measurable distance through digital display module.When the distance between the cars and the obstacles reaches the safety limited level,the acousto-optic alarm module of SCM control will utter a warning signal to achieve the purpose of remind- ing drivers of the potential crash they may encounter.This design thorough- ly functions the features of the microcontroller performance with its hard- ware circuit simple,perfect and complete software function, reliable cont- rol system,therefore,it will definitely give us its usefulness and refer- ence value.