The invention discloses a high pressure water cutting machine for a carpet, and relates to the technical field of automobile carpet processing devices. The high pressure water cutting machine comprises a gantry rack, wherein a horizontal screw rod is arranged on the gantry rack; the horizontal screw rod is connected with a vertical beam through a screw nut; a slide rail is arranged on the vertical beam; the slide rail is connected with a sliding frame in a sliding manner; a water cutter is mounted on the sliding frame; one end of the horizontal screw rod is fixed in a bearing seat I through a bearing and a nut; the other end of the horizontal screw rod is movably supported in a bearing seat II through a bearing; the slide rail is I-shaped; the sliding frame is connected with the I-shaped slide rail through a groove part at the lower part of the sliding frame; the groove part has arc-shaped grooves which are connected with working surfaces on the two sides of the I-shaped slide rail in a sliding manner; roll balls are arranged between the arc-shaped grooves and the working surfaces of the I-shaped slide rail; and lubricating grease is arranged in clearances between the adjacent roll balls. Compared with the prior art, the high pressure water cutting machine can solve the problem that the movement sensitivity of a water cutter of a conventional high pressure water cutting machine for the carpet is poor.