Shape Memory Alloys (SMA) is mainly used in Microsystems because of its micro strain. A new kind of clamping device based on area effect stroke amplifier and driven by SMA wires is introduced in this paper. With the micro strain enlarged by stroke amplifier and pressure transmitted via closed pipeline, a greater displacement can be obtained to clamp the workpiece. This clamping device has prominent advantages in great stroke amplifying ratio and green aspect. Moreover, remote clamping and automatic control are easy to implement because of the high flexibility of fluid.