The upper and lower synchronous feed lockstitch sewing machine has a family-style appearance design, novel and smooth, directly driven by a high-power motor, and strong penetration. The stepping motor can switch the stitch length, and the stitch length can be changed at will. It is simple and convenient, with high degree of overlap of reverse stitching and beautiful stitches. The stepping motor cuts the thread, the sound is soft, and there is no pressure on all kinds of thick threads. The electronic footrest is light and the height of the presser foot can be controlled. The spacious operation space is better for sewing large pieces of fabric, especially suitable for sewing leather, canvas, denim and other mediumor heavy materials.