The accuracy and speed of automatic stacking crane(ASC)gantry positioning affect the efficiency and safety of yard operation to a great extent.Aiming at ASC gantry automatic positioning in automatic container terminal,the paper analyzes and compares the principle and characteristics of magnetic nail positioning,gray bus positioning,laser ranging positioning,BPS positioning and differential GPS positioning.Comparing several factors such as yard layout,capital cost and gantry speed of Qingdao Port automatic container terminal,magnetic nail + rotary encoder positioning is put forward,which is accurate,rapid and reliable.