The invention discloses a method for installing a lamp holder by using a vehicle lamp holder installation fixture. The vehicle lamp holder installation fixture comprises a rotating handle and a fixture rod, wherein the rotating handle is arranged at one end of the fixture rod, and a fixture head is arranged at the other end of the fixture rod; and a clamping groove used for being clamped on a bump on the back side of the lamp holder is formed in the end portion of the fixture head. The installation method comprises the following steps: a bulb on the lamp holder is inserted into an installation hole in the lamp casing; the clamping groove in the fixture head is clamped on the bump on the back side of the lamp holder, and a marking line on the side face of the fixture head is enabled to be corresponding to a marking bulge on the lamp casing; the fixture is rotated through the rotating handle; the marking bulge on the lamp casing is taken for reference, and the fixture rotates for the preset number of turns; and after the lamp holder is rotated and installed in place, the fixture head of the fixture is separated from the back side of the lamp holder, and the fixture is taken down, so that the installation of the lamp holder is completed. The fixture head of the installation fixture is clamped on the bump on the back side of the lamp holder, the rotating handle is rotated, and the lamp holder is rotated and installed, so that force application is facilitated, the lamp holder is installed in place, the installation is simple and convenient, and the installation quality for the lamp holder can be substantially improved.