Abstract: Transplanting is the crucial procedure in agriculture and the energence of transplanters provides convenice for transplanting.In order to improve the efficiency of transplanters and meet the requirement of whole row picking, a strecthing style pick-up device was developed in transplanters.By analyzing its working principle and calculating the key parts of the device.MATLAB GUI was used to verify the movement distance of the key parts of the device, and the key parts were verified and optimized through the target parameters, the movement track of the pin will also be verified.Finally, 3 D printing was used to complete the sample production, continuous photography was used to complete the verification of the trajectory of the pins. Picking test was carried out under different moisture content. When the stretchable piece length is 55 mm, the installation Angle is 74.5°.The results showed that the success rate reached 97.66% by the moisture content was 56.5%.When the moisture content of seedlings is 68.8%, the damage rate of seedlings is 1.25%.