The utility model relates to a city transmission line cable pit field is poor to the waterproof performance of current cable pit between the ditch body and apron and a multi -functional assembled waterproof cable ditch that provide. Including the ditch body and apron, all be equipped with groove structure on the upper end surface of ditch body both sides, be equipped with the cushion in the recess, the integral type is provided with the briquetting that can block respectively to the recess in on apron both sides, and the upper surface undercut of one of them tip of each apron, forms a stair structure, is defined as the step no. One, and the lower surface of lapping another tip is upwards sunken, forms a stair structure equally, is defined as the step no. Two, is equipped with the cushion at the upper surface of a step undercut part, the utility model discloses can effectively improve the waterproof performance between cable pit and the apron, possess two kinds of functions of open -type and underground, at the regional inter -convertible of difference. This structure is the assembled simultaneously, reduces job site wet trade, effectively improves cable pit construction speed.