Floating tray seedling cultivation enables the delivery of water, nutrients, and pesticides through the bottom holes of the trays, offering advantages such as easy management and low production costs, and it has been widely adopted in the southwestern regions of China. A clamp-type elastic seedling picking gripper specifically for floating-tray seedlings was designed. Based on ejection and compression tests of the seedling pots, the mechanical properties of Guofu910 pepper seedling pots were determined. Using ADAMS rigid-flexible coupling simulation experiments, the trajectory of the gripper tip entering the pot was established, validating the rationality of the seedling extraction gripper. A mechanical model of the seedling extraction process was developed, providing a comprehensive analysis of the key factors affecting the success rate of seedling extraction. An orthogonal experiment was conducted by using a single seedling extraction gripper for pepper seedlings, with factors included pot moisture content, gripper width, and extraction depth, to determine the optimal combination of levels for seedling extraction. The results showed that at an extraction depth of 40 mm, gripper width of 5 mm, and substrate moisture content of 55%~65%, the seedling extraction success rate reached 99%, with a substrate loss rate of 3.18%. In adaptability tests across different crops, the extraction success rates for Chama cabbage and tobacco seedlings K326 were no less than 98%, while the success rate for Yunyan 87 tobacco seedlings was 94%, demonstrating good adaptability. This seeding picking gripper demonstrates universally excellent performance, offering raluable reference for row-wise seeding picking in vegetable transplanting machines.