随着火星和月球探测数据的丰富，传统直角坐标重力位模型不适合于这类小天体重力的正反演处理. 针对该问题，本文提供一种基于牛顿引力位的球面模型，并对该模型的重力位进行球谐展开. 发现球面地形的重力位可以用地形及其高阶球谐展开系数进行估算，简化了传统数值积分复杂的求积过程.研究还发现高阶地形产生的影响不超过7 阶，一般取5 阶以内的高阶地形就能满足精度要求.将算法应用于火星表面地形重力位的估算，发现结果与火星表面地形特征较一致，表明本文算法具有一定的合理性.

With the abundance of exploration data of Mars and moon，the traditional

rectangular coordinate gravity potential model is not suitable for the forward and

inverse processing of the gravity of such small bodies. To solve this problem，a

spherical model based on Newton's gravitational is presented，which is expanded by

spherical harmonic expansion.It is shown that the gravity potential of spherical topography can be

estimated by the topography and its higher order spherical harmonic expansion coefficient，which

simplifies the complicated quadrature process of traditional numerical integration.Results also

indicate that the influence of higher topography is less than 7 orders，

and within 5 orders are generally better to meet the accuracy requirements.The algorithm is

applied to the estimation of the gravity potential on the surface of Mars，and the results

are consistent with the topography characteristics of Mars，which shows that the proposed

algorithm is reasonable to some extent.