The invention discloses a constructional ground painting mechanism with a self-feeding function. The constructional ground painting mechanism comprises an upper rail, a lower rail and a painting rack. Two ends of each of the upper rail and the lower rail are respectively fixed on corresponding vertical plates, two ends of each of two rodless cylinders are fixed with sliding blocks, the sliding block on the upper end of each rodless cylinder sleeves the upper rail, the sliding block on the lower end of each rodless cylinder sleeves the lower rail, and a support bar is fixed on the two rodless cylinders; two side plates of the painting rack are fixed on corresponding moving blocks of the two rodless cylinders, and the painting rack is hinged to at least two painting rollers; each painting roller comprises a central rotating shaft, the central part of the central rotating shaft is provided with a central circulation hole, a plurality of axial elongated through grooves are moulded in the sidewall of the central rotating shaft, the axial elongated through grooves are communicated with the central circulation hole, and an outer roller sleeve sleeves the central rotating shaft. The constructional ground painting mechanism with the self-feeding function automatically feeds materials to the painting rollers, and automatically moves to paint the ground, and is good in painting effect and high in efficiency.