Abstract: We intend to manufacture tiny part with SMA, and use it as functional gripper in MEMS assembly. Based on the thermal elastic transformation of alloy and the gripper openness-temperature relation the work principles, dynamic characteristics of the SMA microgripper and the energy transform relation during the gripper working process are discussed in this article. At last, the adhere forces for microgripper in micromanipulation are introduced and the methods to reduce these adhere forces are proposed.