The invention provides a large-scale suspended box cofferdam location fair lead and a location method thereof, and the structure of the invention is a steering device and also a transition device of a fixed seat and a connection plate, wherein, one end of the steering device is connected with the fixed seat through a transverse axis pin; the other end of the steering device is connected with one end of the connection plate through a vertical axis pin; the other end of the connection plate utilizes a plurality of groups of axis pins to combine a traction box through which a fair lead traction rope can pass; the axis pin and a steel sleeve are the bearings of the traction box which is at the end of the connection plate. The location method is as follows: arranging a fixed seat on the outer wall of the suspended box cofferdam; connecting the fixed seat, the steering device and the connection plate through axis pins to form a complete tensile system which can rotate flexibly; installing the traction rope in place by the axis pin traction box after the installation of the fair lead; adjusting the suspended box cofferdam to a specified location and realizing precise location. The invention has the advantages of simple structure, convenient operation, definite stress and low cost which can be used for precise location of other large-scale steel structure devices on the water and on the land, thus having greater promotion value.