The invention discloses a cathode line positioning die and a cathode lien positioning and adjustment construction method. The positioning die comprises a rear measuring rod, a front measuring rod arranged on the front side of the middle of the rear measuring rod and a vertical rod fixed behind the rear portion of the front measuring rod, wherein the front measuring rod and the vertical rod are located in front of the rear measuring rod, the rear measuring rod, the front measuring rod and the vertical rod are straight rods, the rear measuring rod and the front measuring rod are arranged in a perpendicular mode, the rear measuring rod and the front measuring rod form a horizontal positioning rack, and a clamping groove for positioning an adjusted cathode line is formed in the rear side of the middle of the rear measuring rod. The constriction method comprises the steps that 1, anode module installation is performed; 2, cathode line installation construction is performed: when the cathode line is installed on any group of anode modules, the process is that 201, upper and lower fixing frames are installed; 202, preliminary cathode line installation is performed; 203, cathode line positioning, adjustment and fixing installation are performed. The cathode line positioning die is reasonable in design, simple and convenient to use and operate, good in using effect and capable of simply, conveniently and rapidly perform accurate cathode line positioning and ensuring cathode line installing precision.