The invention relates to an adjustable cable support which comprises a support vertical iron, support waling pieces and a plurality of bolts. The support waling pieces are used for supporting a cable; a plurality of screw holes arranged at equal intervals are formed in one side of the support vertical iron; screw holes with the same size as the screw holes in the support vertical iron are formed in the end part of one side of each support waling piece; the support vertical iron is detachably connected with the support waling pieces by the bolts and the screw holes. The adjustable cable support is convenient to disassemble and firm to install, and solves the problems that the position and the mounting height of the cable support cannot be adjusted and manual modification enables construction cost to be increased and the construction progress to be reduced.