The ore deposit is a hypothermal-mesothermal cassiterite sulphide one.It has been revealed through the author's investigation that with the decreasein ore-forming temperature the mineralization stages varied from cassiterite-quartz through cassiterite-sulphides to cassiterite-calcite, and cassiterite sho-wed tendency of growth both in lengths of unit cell axes, especially axis C,and in unit cell dimensions. There exist such admixture elements as Fe in cassiterite which can subs-titute isomorphously for tin. As ionic radii of these elements are usually small,the isomorphism might cause unit cell to shrink. At high temperature, isomor-phous substitution of elements takes Place rather readily, and this probablyaccounts for small unit cell of cassiterite at high temperature and larger oneat low temperature.