The invention relates to the equipment field for hot dip coating with a molten state cladding material and without influences on shape, and concretely relates to an automatic zinc adding apparatus forcontinuous hot dip galvanizing and a usage method thereof. The automatic zinc adding apparatus for continuous hot dip galvanizing comprises a first controller (11), and is characterized in that the apparatus also comprises a second controller (12), a main controller (13), a liquidometer (2), and a crane (3); the liquidometer (2) is arranged in zinc liquid in a zinc pot (10), a suspension hook ofthe crane (3) is arranged over the zinc pot (10), and a zinc ingot (20) is suspended on the suspension hook of the crane (3). The usage method of the automatic zinc adding apparatus for continuous hotdip galvanizing is characterized in that the method is enforced according to the following steps in order: i. zinc adding amount is calculated; ii. a zinc adding instruction is generated; iii. zinc is added. The apparatus and the method can be used for timely monitoring, accurately controlling, and conveniently operating with good adaptability.