Three-row corn precision planter capable of automatically adjusting row spacing

The utility model discloses a three-row corn precision seeder capable of automatically adjusting row spacing, and relates to the field of agricultural machinery. The seeder is characterized by comprising a frame, a suspension, a row spacing adjusting device, a fertilizer discharging unit, a seeding unit, a profiling four-bar mechanism and a press wheel, the suspension is arranged in front of the frame; the line spacing adjusting device is arranged in the frame; the fertilizer discharging single bodies are arranged above the row spacing adjusting device; the profiling four-bar mechanism is arranged behind the row spacing adjusting device; the seeding single body is arranged behind the profiling four-bar mechanism; the press wheel is fixed behind the seeding single body through a pin shaft; a sliding block in the middle of the left-handed and right-handed lead screw is fixed by an optical axis fixing ring; a right-hand thread and a left-hand thread are respectively arranged at two ends of the left-hand and righ