镜像法是求解静电场的一种基本方法.本文通过电容法和电荷法两种方法来求解三金属球体系的多重镜像电荷，进而将带电金属球在空间的电场替代为各个等效电荷和镜像电荷产生的电场.通过对比电场的分布，验证了两种方法的正确性和一致性.进一步的研究结果表明，调节第三个金属球的位置和带电量可以实现两金属球之间的相互作用力由吸引向排斥的转变.结合Matlab 软件，我们直接给出了双球和三球体系时电势在空间的分布.

The image method is a basic method to solve electrostatic field. This paper has used capacitance and charge methods to obtain multiple image charges of a system of three metal spheres. The distribution of electrostatic field is calculated by the effective and image charges. The numerical results confirm the consistence of the derived analytic results. The transition from attractive to repulsive interaction between two metal spheres can be realized by modulating the position and charged quantity of third metal sphere. By using Matlab software，the distribution of electric potential is directly compared for the system of two and three metal spheres.