根据相干合成的原理，建立了三路矩形光束相干合成的数学仿真模型,根据数学模型编写了仿真程序；模拟计算了1～21阶泽尼克像差下，单路矩形光束和三路矩形拼接光束的波像差与光束质量β因子关系的拟合系数；建立了波像差与β因子关系的计算表达式。分析了影响拟合系数的因素，结果表明：拟合系数总体上随着泽尼克像差系数增大而增加。比较了单路矩形光束与三路矩形拼接光束拟合系数的相似点和不同点，并分析了造成拟合系数不同的原因。

A numerical simulation model of coherent combination of three rectangular beams was established. The relationship for one rectangular beam and the combination of three rectangular beams, between the beam quality factor (beta factor) and the Zernike wavefront aberrations of the first twenty-one orders was obtained by numerical calculation through fast Fourier transform (FFT). The formulas of beta factor and wavefront aberration were obtained. Fitting coefficients of one beam and three-beam combination were compared and the affecting factors were analyzed. It is found that the fitting coefficient generally augments with the order of Zernike wavefront aberrations increasing.