Abstract: Abstract: In order to solve the problem of seedlings leakage planting caused by the lack of plug seedlings in trays during with the all automatic transplanter working, an automatic recognition and control device for vegetable plug seedling transplanter was designed. In contrast to the home and abroad information, the design considered the domestic user price affordability and practicality. In this device, a stepping motor was used for driving the seedling disc horizontal motion and another was used for driving the seedling disc vertical motion. Four photo-electric sensors as the seedling recognition device were fitted on both sides of the seedling gripper and seedling disc, which can detect of seedling shortage from four directions. A programmable logic controller (PLC) was used to control clamping seedling gripper motion and the seedling disc transport along horizontal and vertical direction. A touch screen as man-machine interface can set the parameter to fit different size seedling disc, which can also choose manually or automatic control method. In this paper, a comparative experiment f was carried out at different transplanting velocity under the condition of automatic recognition system or one month old pepper seedling. The results showed that it could work effectively. The movement of the seedling trigger photoelectric sensor produced a signal, so that the seedlings were stopped and clamped away when moving to the position of the seedling gripper. On the contrary, the lack of seedling lattice cannot trigger photoelectric sensor, on arrival will not stop the seedling fetching device position, but quickly through, directly send the next seedling to stop on position of the seedling gripper, waiting for the clamping seedling gripper. This improves the seedling grab efficiency, reducing the leakage rate of transplanting machine plant. Automatic recognition and control device had low misjudge rate when transplanting speed was form 60 to 120 seedling per minutes. When transplanting speed was from 60 to 90 seedling per minute, the transplanter had well leakage plantings rate and throwing seedlings rate that can effectively work at transplanting seedling. The response speed of automatic recognition and control device can work at high speed transplanter. The leakage transplanting rate with automatically seedlings picking recognition control system was 12% lower than without the automatically seedlings picking control system. The device achieved the objective of reducing leakage rate purpose. Relative to not used for automatic identification of transplanting seedling mode, it is reduced about 12% that the leakage rate of the whole system of plant in 60-90 seedling /min transplanting speed. Leakage rate of transplanting machine plant is close to the practical level of planting. It achieved the purpose of reducing the leakage rate of planting.Through observation and analysis during experiments, if the conveying of seedling disk was changed to horizontal, it can maximize the seedling erect and reducing sensor misjudgment caused by seedling roll or tilt, the identification rate was improved. The system was only carried out in the laboratory test, but field test has not yet performed. In field operation, some factor may affect the automatic recognition and seedling fetching device reliability and stability, such as vibration of machines, interference of the sensor by sunshine outdoor. These need further test and examination. More field experiment needs to be tested for the influences of machine vibration and sunlight to the photoelectric sensor.