Simulation of blood flow is a very important component in the virtual system of cardiac intervention system. Real-time and accurate simulation of blood flow can make the virtual surgery more realistic. This paper addresses the problem of the simulation of blood flow in virtual cardio-vascular objects. With an analysis of the physical model of cardiac-vascular blood flow in the artery based on the Windkessel model and by drawing the blood with improved particle system, this research successfully simulated the blood flow inside the vascular, thus satisfying the need of being real-time and realistic for the Cardiac intervention system.