Abstract: It is time-consuming to obtain the matched devices by manual analysis and place them in hand for analog circuits of the mixed signal system.In order to shorten the design cycle,reduce the cost of integrated circuit design,this paper develops the tool for analog integrated circuit layout design automation with C++language.Because the modes of matched device groups in analog circuits are different,according to the characteristics of different matching styles,we edit the corresponding algorithm for automatic placement,so as to shorten the design cycle and reduce design cost.And the experimental results verify the automatic placement algorithm of matched device groups.