Abstract: This paper presents a high precision data acquisition system with LM231 A/F transform chip and single chip microcomputer with low cost.The V/F transformer is characteristic of high precision,high linearity it can be with simple peripheral circuit,easy to realize A/D trans- form for measurement of analog in the field of industry.The single chip microcomputer is direct to interface with LM231 chip that has the light -electricity coupling circuit,to improve system working security.Full use of resource of hardware and software,the system identifier rate reaches 12 digits and its accuracy is 0.02%.The system is available for use in the field of measurement and control of temperature system, voltage,current intensity,methane density,etc.In the case of long distance between sensitive and upper computer,we can use RS-485 in- terface or wireless data transmitting/reserve module to remote data communication.