According　to　the　theory　of　crystallization　chemistry,　thermodynamics　and　kinetics,　the　process　of　droplet-like　phase-separation　of　CaO-Al2O3-SiO2　glass　was　simulated　by　using　TEM,　image　analyzer　and　computer.　The　mathematics　and　logical　model　of　phase-separation　was　developed　on　the　basis　of　phase　transition　theory　and　experiments.　The　key　factors　of　following　logarithmic　normal　distribution　are　that　critical　sizes　of　droplet　phase　nuclei　must　change　in　a　certain　range　for　the　droplet-like　phase-separation　controlled　by　the　mechanism　of　nucleation-growth;　relative　growth　rate　of　droplet　phase　locates　at　5%-10%.　The　distribution　type　has　no　relationship　to　the　absolute　values　of　critical　sizes　when　phase-separation　takes　place,　and　to　the　droplet　phase　diameter　when　the　droplet　phase　stops　growing.　This　simulation　method　leads　to　a　new　way　to　control　nanometre　structure　of　glass　and　make　a　noval　glass　materials　with　some　special　properties.