将入射高斯波束用球函数展开，采用有限项级数展开的方法计算了高斯波束的波束因子，并根据声波散射理论，推导出球形粒子在偏离高斯声波轴线时散射波形函数的解析表达式，研究了高斯波束的波束宽度、离轴的距离等参数对声散射特性的影响.通过数值仿真，给出了刚性球形粒子在高斯波束作用下的散射声场的空间分布.仿真结果表明：随着波束宽度的增加，散射波形函数的幅度逐渐增大，当波束宽度为20倍的波长时，其散射波形函数曲线和平面波的完全吻合；随着粒子离轴距离和角度的增大，散射波形函数的幅度逐渐减小.该研究为利用聚焦波束实现粒子操控提供了理论依据.

The incident Gaussian beam is expanded with spherical harmonics function and the beam factors of Gaussian beam are calculated using the finite series methods. The analytical expression of scattering form function is deduced according to the theory of acoustic scattering for spherical particles lies off the axis of Gaussian beam. The effects of the beam waist of the Gaussian beam and the distance from the Gaussian beam center on the characteristics of acoustic scattering are investigated. Using numerical simulations, the scattering patterns of rigid spherical particles in the Gaussian beam are obtained for different conditions.Our results show that: the amplitude of scattering form function gradually increases with the width of beam, and when the beam waist is 20 times the wavelength, the scattering form function is consistent with plane wave exactly. The amplitude of scattering form function gradually decreases with the particles off-axis distance and angle.Our results provide a theoretical basis for the particle manipulation relied on focused beam.