The invention relates to an automatic solar tracking system which tracks the sun accurately in real time and is used for efficiently collecting and using solar energy. The automatic solar tracking device comprises a solar energy photovoltaic array, an adjusting device connected with the solar energy photovoltaic array and used for adjusting the position of the solar energy photovoltaic array, a stand column for supporting the adjusting device and a control system. The adjusting device is composed of a pitch angle adjusting assembly and a position angle adjusting assembly, wherein the pitch angle adjusting assembly is connected with the position angle adjusting assembly through a vertical shaft, the position angle adjusting assembly is arranged on the stand column, and the control system is used for performing closed loop control on the adjusting device. The accuracy in solar tracking of the automatic solar tracking device is smaller than 0.1, the energy consumption only occupies for 0.5% of the electric energy production of the driving photovoltaic array, and the automatic solar tracking system has the advantages of being long in service life, intact in protection function and the like.