The invention discloses a wiring support capable of adjusting the width of a wiring duct, and the support comprises: a first end plate and a second end plate, wherein the first end plate and the second end plate are respectively provided with at least one wiring through groove, a first supporting plate is slidably connected with a second supporting plate, the first supporting plate is provided with a plurality of first connecting parts in the sliding direction of the first supporting plate, and the second supporting plate is provided with a plurality of second connecting parts in the sliding direction of the second supporting plate; and a separation piece which comprises a turnover part, a first turnover plate and a second turnover plate, the first turnover plate and the second turnover plate are connected through the turnover part, the first turnover plate and the second turnover plate can be turned over along the turnover part, the end, away from the turnover part, of the first turnover plate is detachably connected to any first connecting part, and the end, away from the turnover part, of the second turnover plate is detachably connected to any second connecting part. Accordingto the invention, the sizes of a plurality of wiring spaces can be adjusted by sliding the supporting plate, the operation is more convenient, and the adjustment is simpler.