Abstract: A diamond polishing disk and a manufacturing method thereof are described. The method includes the steps as follows. A plurality of diamond particles are disposed in an accommodation unit, and each diamond particle has at least one acute polishing end. Next, a guiding mold is supplied, in which the guiding mold has a plurality of grooves. The guiding mold is pressed on the diamond particles, such that the acute polishing ends of the diamond particles are respectively inserted in the grooves correspondingly. Next, the guiding mold is removed, and then a polymer material is injected into the accommodation unit to cover the diamond particles. The polymer material is hardened. Finally, the accommodation unit is removed, so as to finish manufacturing the diamond polishing disk.