Objective Real-time three-dimensional echocardiography (RT3DE) is an important method for heart hemodynamics research. Traditionally the whole research process has to divide to the following two phases: firstly render the heart full-volume data from RT3DE and then find the optimal cutting planes of it with manual operation. Such procedure not only spent too much time but also difficultly to handle. Now, the new method could be used to implement the extraction on personal computer automatically. Methods With the help of the video card with graphic processing unit, we reconstruct the 3D image of the heart based on personal computer and demonstrate the improved entropy for the optimal cross section selection with correlation coefficient method. Results We have completed the whole process in C/C++, with the help of OpenGL Library. We also add some segment into the program to speed up the hardware with Cg language on GPU (Graphics Processing Unit). Conclusion This new method could satisfy the doctor's clinical need with the better veracity and higher cartography speed.