采用最小偏向角法在40 ℃ ~160 ℃范围内分别测量了0.194、0.254、0.404、1.53、2.325 μm等9个波长下非线性光学晶体YAl3(BO3)4(YAB)的折射率，通过最小二乘法拟合得到不同温度下折射率的Sellmeier方程及折射率温度系数随波长变化的函数表达式。在此基础上计算出YAB晶体I类相位匹配实现266 nm紫外光输出时的温度带宽为6.9 ℃·cm。实验与计算结果表明，YAB晶体具有较好的热稳定性，有利于实现高功率、高稳定性的266 nm激光输出。

The refractive indices of nonlinear optical crystal YAl3(BO3)4 (YAB) for nine wavelengths of 0.194, 0.254, 0.404, 1.53, 2.325 μm and so on under the temperature range from 40 ℃ to 160 ℃ are measured by the prism minimum deviation method．The Sellmeier equations at different temperatures and the relationship between the thermal coefficients of refractive index and the wavelength have been obtained by the least square method. The calculated acceptance temperature for type I phase-matching of YAB crystal for 266 nm ultraviolet light generation is 6.9 ℃·cm based on the above equations. Both the experimental and theoretical values show that YAB crystal may be an ideal nonlinear optical crystal for 266 nm harmonic generation with high power and high stability because of its good thermal stability.