The invention relates to the technical field of cold rolling and pickling line, in particular to a welding equipment and a welding process for a plastic pickling groove . The welding equipment is composed of a worktable, rails, a walking trolley, a machine base on the trolley, a horizontal sliding mechanism, an adjustment screw, a slant sliding mechanism and a welding device. The welding device iscomposed of a motor, a reduction gear, an auger delivery device, a heater and a welding head. The welding process comprises the following steps: the adjustment screw adjusts the degree of inclinationof the slant sliding mechanism, welding material is added into a feed hopper, the power supply of the heater is powered on, the temperature of each heating zone of a machine barrel is respectively controlled in the range as a first zone below 190 DEG C, a second zone below 230 DEG C, and a third zone below 280 DEG C, and the moving speed is controlled to be 0.05-0.08 m / s. The invention has the advantages that the welding quality is improved, and the weld seam factor can reach above 0.9; the equipment is convenient to install and maintenance free, and has long service life. The weld seam is formed in one time, no repeated factory build-up welding is required; the weld seam is free from pore, undercut and over burning, with smooth surface and graceful form, needs no dressing, and is corrosion and ageing resistant.