The invention relates to an automatic control system and an automatic control method for a tower crane. The system comprises a tower crane system, a GPS positioning system, a hardware control system,a wireless communication system and an upper computer control system. The tower crane system comprises a large arm/trolley/a lifting hook motor. The GPS positioning system comprises a GPS fixed base station and two handheld base stations, the fixed base station is located at the top end of the tower crane, and the handheld base stations are carried by staff at a construction point and a material point; the hardware control system comprises a large arm/trolley/lifting hook frequency converter and an encoder; the wireless communication system is used for transmitting position information, motorrevolving number of turns and angle to the upper computer control system; the upper computer control system is used for outputting a reducing time and a reducing point of the large arm/trolley/a lifting hook motor; and a trolley motor and a lifting hook motor are provided with steel wire rope winding mechanisms. The automatic control method for the tower crane comprises two modes: a following automatic drive mode and an automatic drive mode in a fixed route between two points. According to the following automatic drive mode, a lifting hood of the tower crane follows the staff at the material point to move automatically. According to the automatic drive mode in the fixed route between two points, the lifting hood of the tower crane can move in a reciprocating manner between the material point and the construction point.