This paper introduces a novel gecko-inspired gripper for flat surfaces based on mushroom-shaped adhesive microstructure. Attachment and detachment model is established according to the adhesion mechanism of gecko. The influence of different physical parameters on adhesion are analyzed. On the basis of this, an adhesion unit model is proposed, and a micro gripper with controllable adhesion is developed. Furthermore, the grasping ability of the gripper in different conditions is tested. This work provides new insights into the application of bio-inspired adhesives to grippers.