In order to obtain high uniformity and freepyro black LiTaO3 wafers, the reduction treatment of the 42° rotated Ycut LiTaO3 wafers was carried out by chemical reduction under a mixed powder. The results showed that the bulk electrical resistivity was 3.98×1010 Ω·cm, optical transmittance was 36.5% at 365 nm, the uniform of optical transmittance was 1.15, the thermal conductivity was 2.66 W/(m·K) and the coefficient of thermal expansion was 2.79×10-6 K-1 by chemical reduction, which met the applications requirements for SAW devices. The results of the verification test of SAW devices further confirmed that the antistatic effect of the LiTaO3 wafer was good, the yield was high and the uniformity was high.