Abstract: In order to solve the problem of precise visualization and description of cardiac fluid state,a new streamline visualization method of cardiac fluid motion based on color Doppler image information according to the characteristics of cardiac flow field is studied.This method represents threedimensional flow in two-dimensional observation area with point sources and point sinks,and calculates Doppler flow function value by expanding the stream function principle.It regards point sources and point sinks as the start points and end points of plane streamline respectively,then draws plane streamline on the basis of the principle that Doppler-flow-function values are equal in the same streamline.According to the method,vortex streamlines of cardiac flow field can be obtained by selecting the closed curves from plane streamlines also.Experimental results show that the proposed method can effectively realize visual description of cardiac fluid state,and effectively describe vortex motion state in the two-dimensional observation plane,and provide a new method for the effective visualization and precise quantification of cardiac fluid state simultaneously.