The papers about human action simulation mainly focus on the action taking place on the land because it gets much harder to take fluid dynamics into account when the simulation happens in the water. Our work is expected to propose a simpler approach to simulate the human swimming. First, we use a simplified human model and edit a sequence of swimming action. Then we transform each part of the model into a sphere with the same volume, which makes it easier for our calculation. By this way, we attain the force of weight, buoyancy, drag, and thrust. These forces act on the model, which make the model move and rotate, so we have the simulation of human swimming. At last, real-time generated wave is added into our simulation to make it looks more real.