The invention relates to the technical field of automatically tracking the sun, and discloses a method for automatically tracking the sun and an automatic tracking system. The automatic tracking system comprises a photoelectric tracking system and a tracking actuating mechanism, wherein the tracking actuating mechanism comprises an east-west sun-around rotating mechanism and a north-south sun-around angle regulating rotating mechanism, the sun-around angle rotating mechanism comprises a ring gear 4 and a pinion 5 which are meshed and connected, the pinion 5 is connected with a stepping motor and arranged on a supporting base 6, two ends of the ring gear 4 are hinged with a main shaft 7 arranged in the center of a solar panel support 8, and the main shaft 7 rotates relative to the supporting base 6, a gear 3 arranged on the main shaft 7 is meshed and connected with a gear 9 arranged on a stepping motor shaft fixed on the solar panel support 8, and the solar panel support 8 rotates relative to the main shaft. According to the invention, the movement of solar rays can be automatically tracked, the plane where an energy transformation component of solar energy equipment is ensured to be vertical to the solar rays all the time, and the energy utilization ratio of receiving equipment is increased.