Yb-doped yttrium aluminium tetraborate YbxY1-xAl3(BO3)(4) (Yb: YAB) has been grown by flux method, with large sizes and good optical quality as well as different Yb3+ ion densities of 8-15 at% in the lattice structure. This crystal belongs to the trigonal system with point group 32, conforming space group R32. The density of Yb: YAB is 3.844 g/cm 3 for a content of 8%. The absorption and fluorescence spectra have been measured. The laser of Yb: YAB crystal can be demonstrated when it is pumped by a laser diode (LD) at a wavelength of 977 nm. Cw green output (1.1 W) has been obtained with a high beam quality and a diode-to-green optical conversion efficiency of 10%, and wavelength tunablity from 513 to 546 nm has been demonstrated. To the best Or Our knowledge, this is the highest green power achieved for self-frequency-doubling crystals so far.