The latest progress in the study of optical homogeneity and weak-absorption of large-sized sapphire crystal (φ113 mm×70 mm) is reported. The polishing precision of the whole crystal surface reaches 1.666λ, and the transfer wavefront distortion is 0.584λ. The transmission is higher than 80% at UV waveband and than 86% at VIS-NIR waveband. The weak-absorption coeffcient is 35×10-6 /cm～65×10-6 /cm.