Effects of nano-SnO2 or nano-Yb2O3 on crystallization property of fused quartz ceramics were studied by XRD and measurement of thermal expansion rate from the perspective of crystallization. The results indicate that cristobalite as the main crystal phase would crystallized in the fused quartz glass at high temperature, and the amount of cristobalite increases with increasing of sintering temperature; the addition of nano-SnO2 or nano-Yb2O3 effectively decreases the expansion ratio of the fused quartz ceramic materials during temperature elevating process by inhibiting crystallization of cristobalite, and with increase of sintering temperature, the dosage of additive necessary to keep the fused quartz ceramic materials with a low expansion ratio was adjusted, the optimum dosage (mass fraction) of nano-SnO2 or nano-Yb2O3 as crystallization inhibitors is 1% and 2%, respectively.