The kinetics is one of the important subjects on the petrology. In this paper the theory and method of the crystal size distribution(CSD)and its characteristics in some simple geological processes are intrudu}ed..And an appraisal was raised for CSD according to a) theoretically and the practical application，b) the natural geological processes, c) the calculating results of two to three dimensions in some rocks, and d) the geochronology. It is suggested that 1) the natural geological processes are very }omplirated and have some effects to CSD, 2) the errors of calculating from two to three dimensions in some minerals with the]ow-grade symmetric crystal system could be easy eliminated by the orientated measure, and 3) the crystal growth time has ageochronological significance under some conditions.