Abstract: Abstract: As one of special rice seedling, the pot-blanket seedling is a method between the rice pot seedling and blanket seedling. Because of its low damage to seedling and root while transplanting, fast reviving, and earlier rooting and tillering after transplanting, the mechanical planting of pot-blanket seedling is enabled to be high yield and more efficient. Compared with the ordinary seedling, its yield can increase 5%-15%. In China, rice is the principal food, so it is very significant to research the planting technology of pot-blanket seedling. However, there is no existing transplanter specially for pot-blanket seedlings. Vertical feeding-seedling device of existing high-speed transplanter being used has following problems: 1) With the influence of gravity and vibration, seedlings will slide down on flat belt，when vertical feeding-seedling device does not work and cannot be fixed. 2) One-way bearing can also be rotated unidirectionally with the force of vibration so that seedling cannot be fed accurately. 3) The accumulative transmission error of one-way bearing will increase with time. As a result, the vertical feeding seedling cannot be quantified accurately. In order to solve the problem that vertical feeding seedling is impossible to be quantified accurately with use of high-speed transplanter, in the paper, a new kind of rice pot-blanket feeding-seedling device was designed and improved for rice pot-blanket seedlings. After analyzing and summarizing the planting traits of rice pot-blanket seedling on references at home and abroad, a device with intermittent rod mechanisms, four-bar mechanism, a double-ratchet mechanism which applies to platform of high-speed transplanter was analyzed theoretically and structured to satisfy the requirements of rice pot-blanket seedlings. By used of Solid Works, it will be enabled to test its work conditions in virtual simulation. And a prototype was successfully developed. The experiment showed that the deviation of one-pass vertical feeding quantity was less than 2 mm and there was no accumulative error after repeated feeding. In the condition of high-speed operation, vertical feeding seedling was accurate and stable. The position of seedlings can be fixed when the device under inactive condition. The research can provide a reference for design and application of rice transplanters.