This paper introduces a type of large scale scanning probe microscope, which adopts the scheme of the separation of large scale scanning from high precise scanning, and the separation of X - Y scanning from vertical detection. The instrument has the advantages such as good repeatability, large scanning scale as well as high resolution. The large scale scanning range is 220 mm × 290 mm × 60 mm and the repeatability is 2～3/μm. The instrument achieves the auto-feeding of the probe, the auto-focusing of the optical microscope and the auto-mosaicking of the scanning image.