The invention discloses a height adjustment fixing base for a faucet before and after installation. The height adjustment fixing base comprises a first fixing base and a second fixing base; the first fixing base is fixed on the wall surface; the second fixing base sleeves a faucet water pipe and is connected with the faucet water pipe in a fastening mode; the second fixing base is provided with a connecting arm which can be arranged in the first fixing base in an insertion joint mode; a plurality of first screw holes which are continuously distributed are formed in the first fixing base along the insertion joint direction of the connecting arm; the connecting arm is provided with second screw holes which are in one-to-one correspondence to the fist screw holes; the connection between the first fixing base and the second fixing base is fastened through a first screw so as to fix the faucet onto a wall surface. According to the height adjustment fixing base for the faucet before and after the installation, the adjustment on the distance between the faucet and the wall surface and the height position of the faucet is implemented through the structural design, the height adjustment fixing base can be applied to the installation of different types of faucets due to the high versatility, the problem that the alignment of the previous faucet cannot be achieved due to the fact that the position of a water pipe is not equal to the height of a faucet installation base during installation is solved, the great use convenience is brought to the faucet installation personnel, and the installation efficiency of the faucet is improved.