Abstract: At different tempertures and changing the filling time, three different fillers including cedar wood oil, castor oil and liquid paraffin are chosen to fill emerald's gap and improve its transparency. The viscosity of fillers are reduced and their flow ability is improved upon increasing the filling temperature 60℃ is found to be a sultable temperature after optimizing the filling process. If static injection method and vacuum impregnation method are used, 1 d is the most suitable length of time. Under the same condition, similar results are obtained after filling the beryl and the emerald. Infrared spectrum is empolyed to characterize the filling materials. The characteristic absorption peaks of cedar wood oil appear at 3 065, 2 957 and 2 872 cm^-1, while those for castor oil are at 3 012, 2 927 and 2 854 cm^-1, and for the liquid paraffin are at 2 955, 2 924 and 2 854 cm^-1.