Abstract: Yttrium silicate nanocrystallites were synthesized by the microwave-hydrotherma1 method using Y(NO_3)_3·6H_2O, Na_2SiO_3 and NaOH as raw materials. The influence of solution composition, synthesis temperature and annealing temperature on the phase and microstructure of yttrium silicates crystallites were investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the powders. The results showed that Y_2SiO_5 content increase as the synthesis temperature increasing. The increase of annealing temperature is benefit for the growth of yttrium silicates crystallite. Y_2SiO_5, Y_(4.67)(SiO_4)_3O and Y_2Si_2O_7 crystallites with the particles size of 400-600 nm、200-400 nm and 400-600 nm can be achieved, using different initial solution composition under microwave hydrothermal at 150 ℃ for 10 min and annealing at 900 ℃ for 2 h,and the crystal is best.