The basic formulas about particles distribution under outside force fields, such as Van't Hoff formula, Kelvin formula and sedimentation equilibrium formula of colloid have been proved by using Boltzmann distribution law. The moulds are clear and the method is simple and convenient. 应用玻尔兹曼分布定律证明了范特霍夫渗透压公式、开尔文公式、胶体粒子沉降平衡公式等与粒子在外力场中分布有关的基本公式,模型清晰,方法便捷。