Medical catheter plays a very important role in the minimally invasive cardiac surgery. Doctors want to know the real-time location of a catheter when the catheter is navigating in the heart. This paper studies on simulation of interaction between heart and catheter based on BD tree. The heart data are collected from hospital and a heart model is reconstructed using the Poisson algorithm. The catheter tip is simulated by a sphere, and its movement is controlled by keyboard. The nearest point of the catheter tip on the heart model is got in real time based on BD tree. The distance between the catheter tip and the heart is calculated by the distance between the center of sphere and the nearest neighbor point in the heart model. A projection of the catheter tip in the heart model is applied, while the color of the projection changes along with the distance. The development platform is OpenGL combined C++ language.