The invention discloses a supporting anchor horizontal displacement monitoring device which comprises an adjusting seat arranged at the bottom end of a monitor body, a support seat connected to the bottom end of the monitor body through the adjusting seat, a positioning rod fixedly connected to one side of the top end of the support seat, and an annular clamping groove formed in the outer side of the circumference of the middle of the positioning rod. A positioning groove is formed in the side, right opposite to the positioning rod, of the bottom end of the adjusting base, sliding grooves are symmetrically formed in the positions, located on the two sides of the positioning groove, in the adjusting base, clamping beads are slidably connected into the sliding grooves, sliding blocks are arranged on the sides, located on the clamping beads, of the sliding grooves, and springs are arranged on the sides, located on the sliding blocks, of the sliding grooves; according to the device, a precise monitor main body is not changed, only a positioning groove in an adjusting seat at the bottom of the monitor main body is aligned with a positioning rod and is pressed downwards to be assembled and applied, and only the position between a through hole in a limiting piece and a limiting rod needs to be adjusted, so that the direction of the monitor is flexibly adjusted; the device is very suitable for being quickly put in horizontal displacement monitoring of the support anchor.