The surface characterisitics and physical properties of the droplets spreading on cylindrical surface and V-shaped cavity are investigated. Based on the experiemnt results, Surface Evolver is employed to simulate morphology changes by minimizing the total energy of the system, and the simulation results agree well with the experimental results. Otherwise, the relationship among the contact angle, the dorolet volume, the diameter of the tubes or the included angle of the substrate is discussed. The theoretical shapes and feature parameters including the droplet height, the spreading distance, the contact area and the surface energy that are hard to obtain by experimental measurement are given. A mathmatical-physical model is established and a finite element analysis method is supplied to describe the surface properties of molten droplets on different types of substrates, which provides theoretical guidance and necessary parameters for developing interface science and studying wetting mechanism bewteen solders and substrates.