Large optical-quality Yb:YAl3(BO3)(4)(Yb:YAB) crystals have been grown by the flux method. The thermal properties of Yb:YAB crystal were measured for the first time. The thermal properties of Yb:YAB crystal with different Yb3+ ion concentrations are also reported. The results show that the ytterbium concentration influences the properties of Yb:YAB crystal. The specific heat decreases with the increase of Yb3+ ion concentrations in the experiment range. Apparently, the thermal expansion coefficient increases along the c-direction with the increase of Yb3+ ion concentrations, while it changes slightly along the a-direction. The output laser in 1120-1140 nm ranges has been demonstrated pumped by InGaAs laser. The slope efficiency is 3.8%. The self-frequency-doubling output power of 1 mW is achieved. (C) 2003 Elsevier Science B.V. All rights reserved.