The invention discloses an optical fiber distance measurement system and an optical fiber distance measurement method. After improvement, an end face of an optical fiber array to be detected is arranged nearby a front focal plane of a microscope objective and an object distance is slightly greater than a focal distance; a sampling diaphragm is arranged on a rear focal plane of the microscope objective; and an image sampling chip is arranged on an image plane of the microscope objective. A coherent light source is divided into a plurality of paths through a light splitter and the light paths are connected into tail fibers of the optical fiber array to be detected respectively and are emitted out from end faces of optical fibers; the light sequentially passes through the microscope objective and the sampling diaphragm and is emitted onto the image sampling chip to obtain images of light spots on the end faces of the optical fibers; then the images are analyzed through an image processing module to obtain optical fiber distance information. The sampling diaphragm is adopted and a replicating array of a light spot image sample is obtained on the image plane; the array distance depends on the period of the sampling diaphragm and is used as a reference scale in a measurement process; and standard parts needed by a conventional testing system can be removed and the testing efficiency is improved.