The invention discloses a shipway hull digital positioning auxiliary tool and a use method thereof. The auxiliary tool comprises a chassis, a supporting pipe, a thread bushing, a vertical threaded column, a clamping groove, a clamping groove built-in block, a fixed seat and a rotary target. The supporting pipe and the chassis are fixedly connected, the thread bushing and the supporting pipe are fixedly connected, the vertical threaded column and the thread bushing are in threaded connection, the clamping groove is formed in the top end of the vertical thread bushing, the clamping groove built-in block is arranged in the clamping groove, four threaded holes are formed in the clamping groove in the circumferential direction, a front threaded column, a rear threaded column, a left threaded column and a right threaded column are in threaded connection with the threaded holes separately, the bottom end of the fixed seat is fixedly connected with the top end of the clamping groove built-in block, and the bottom end of the rotary target is fixedly connected with the fixed seat. Auxiliary tools are arranged on the two sides of a shipway, by means of three-dimensional adjustment of the rotary target, shipway grid reference lines are converted into three-dimensional coordinates of the rotary target, efficient and precise digital hull carrying positioning is achieved, and the use processis convenient and precise.