In this paper,we used ?1.2mm ER-GH4169 welding wire to prepare columnar array structure on 5mm thick Q235 carbon steel substrate by CMT-Pin additive technique,and investigated the Pin forming process and tissue characteristics.The results show that when the Ball/Cyl Adaptation parameter is negative,the Pin head shape is Cylindrical;when the Ball/Cyl Adaptation is non-negative,the Pin head shape is Ball;Altitude Adaptation controls the height of Pin growth,and the Pin height is obtained between (2.30~4.96)mm.The microstructure of Pins is divided into Pin axis zone,fusion zone,and base material zone;Pin axis area has a large number of columnar crystals,which grow outward along the axis; in the fusion area,the columnar crystals change from fine crystals to coarse crystals along the Pin axis upward,and the fusion area is a very fine fusion line,with a large number of strips of Laves phase precipitated between the crystals;in the base material area,there is a tissue of light and dark interlayer.