A large NaX type zeolite crystal of a uniform particle size of 20$mu extrm{m}$ are grown with various {{{{{H}_{2}O}}}} content by hydrothermal reaction and added seed crystal (2~3$mu extrm{m}$) to reactant solution as a function of different adding seed levels from 3 to 15%. The result that increased purity of NaX zeolite above 95% and homogeneity of crystal size by increasing adding seed levels, also decreased crystallization time. It was explained that adding seed to synthesis solution leaded out increase of surface area for physical contact reaction and directed growth of seed crystal, so more rapid consumption of reaction gel as increase seeding levels.