Recently, heavy rainfall has occurred frequently, and the rainwater drainage design of buildings becomes increasingly important. For the rainwater drainage design of buildings with complex shape, it is necessary to simulate the water flow on building surfaces. Although the surface tension and resistance force are critical factors which affect the characteristics of water flow on building surfaces, it is not clear how the modelling of these forces in the MPS method affects the prediction accuracy of water flow on building surfaces. In this study, the water flow velocity on the vertical wall was simulated by using the MPS method with the surface tension model and dynamic contact angle model as the resistance force model. From the simulation results, we investigated the influence of these models on the prediction accuracy of water flow velocity on the vertical wall. The potential model was used as the surface tension model. When the effective radius of potential model was set to 3.1d (d is particle diameter), the relationship between the water flow velocity and flow rate from experimental results was not reproduced. The MPS method overestimated the water flow velocity at low flow rate and underestimated the water flow velocity at high flow rate. By setting the effective radius of potential model to 4.6d or more, better correspondence between the water flow velocity and flow rate was obtained and the prediction accuracy of the water flow velocity at low flow rate was improved. This is likely because the potential force between fluid particles for each flow rate was reproduced by increasing the effective radius of potential model. The influence of the type of dynamic contact angle model on the prediction accuracy was small.