A method of using the photothermal effect in the direct measurement of diffusivity of nanometer materials is reported. Experimental results at different shape pressures and sintering temperatures are given. The results indicate that the diffusivity of nanometer ZrO2 increases with the shape pressure decreasing, while for nanometer A12O3, at higher sintering temperature, the diffusivity decreases with the sintering temperature elevating, and at lower sintering temperature the diffusivity unusually rises.