Magnetostrictive measurement principle and the parameters are outlined，which is designed to replace　commonly used semiconductor strain gauges of aluminum wire resistance strain gauges，the development of a new type of semiconductor micro - displacement sensor，and measuring the standard length of the micro - displacement sensor calibration. It can be used to measure directly a small length of the material in a magnetic field variation. 　Which addresses the teaching experiment that could not easily replace the original samples of the trouble，but also improves the measurement sensitivity and accuracy，a variety of materials accurately measured the magnetostriction coefficient curve.