Abstract: Planting vegetables and flowers mostly need enormous seedling supply. It is inevitable to realize the seedling produce and supply automatically, so as to turn the traditional agriculture to the modern agriculture. According to traditional process for planting, an automatic seedling production line was designed, which taking the AT89S52 microcontroller as the core, taking the interface chip of 8255A as the I/O extended port to control all of the motors. The production line is combined the five traditional hand-made seedling procedures together: soil base filling, soil base pressing, seeding, covering and watering. The automatic line experiments were conducted in the lab, and the test results showed that it worked smoothly and stably. This research provided a reference for the design and manufacture of automatic seedling line in the future.