This paper introduces the measurement and control system of a kind of detector of metallurgical slag conductivity, Illustrates the general structure of the measurement and control system, the task allocation of every unit, the performance indicators and the way of data exchange etc, Focuses on the theoretical derivation of the control algorithm that is adopted for improving control accuracy and effectiveness in the process of slag temperature control, Describes the Computer programming methods and the special way for low-cost used in strong electric circuit design and control software programming, Shows the principle analysis of melt conductivity measurement the Implementation way to get accurate and reliable data. A great deal of practice has proved the detector has high accuracy, stable performance, simple operation, and a higher cost-effective.