5mol%YF_3-CaF_2 nano-power was prepared by direct precipitation method with Ca(NO_3)_2, Y(NO_3)_3 and KF as raw materials. The influences of pre-sintering temperature and sintering temperature on the particle size and distribution of 5mol%YF_3-CaF_2 nano-power were studied by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The results show that 5mol%YF_3-CaF_2 nano-powder prepared by direct precipitation exhibits calcium fluoride fluorite structure; at the concentration of 5mol%, the doping ha...