Kelp seedling cultivation is operated manually in many coastal cities, which is highly labor-consuming. For the traditional gripping equipment for kelp seedling, the rate of seedling is low, and the service life of the grippers is short. In view of this, improvements have been made to the driving parts of the gripper for kelp seedling. In this paper, the selection basis of the design scheme of the gripper for kelp seedling gripping was firstly introduced; then the typical mechanical structure of the gripper for kelp seedling gripping was improved; finally, the optimal parameters of the loosening of the gripper for kelp seedling gripping are determined by experiment. The results showed that the connecting rod and CAM mechanism have been reasonably merged into the coordinated action of the gripper for kelp seedling gripping, meanwhile the three movements "gripping-loosening,-drawing close to form a hole" was completed, thus the kelp rope for inserting seedling "clamping-loosening,- inserting seedlings" automation was achieved; By experiment, it is determined that the length of the gripping length is 60mm, the torque required for changing the angle of 5o ~ 10o is small, and the hole is easy to be formed. The research shows that the gripping motion can be completed in a short time, which can provide a reference for the development and application of the seedling gripping device of Marine plants, thus having a good prospect for development.