Based on the magnetostrictive effect of giant magnetostrictive material, an intelligent microdisplacement actuator was designed and its structure and working principle were discussed. In order to further explore the output micro-displacement characteristics of the designed giant magnetostrictive actuator, a corresponding output micro-displacement testing system was built. The results show that the output micro-displacement of the actuator reaches the maximum when the pre-pressure reaches 300 N in a certain range. The output micro-displacement increases with the increase of the input current when the pre-pressure is less than 300 N and the output micro-displacement decreases when the pre-pressure exceeds 300 N.