In the frame of the distributed video coding, the exact estimate for the statistic between the WZ frame and assistant side information, the exact model and estimated parameters for virtual correlative channel is important to improve the coding compress efficiency and the control of the code rate. The model selection and parameters optimization for analog channel were discussed. The Laplace model and the Gauss model in common used in the video frequency were researched. An estimate method of parameters with emendation coefficient for virtual correlative channel was presented, and the estimated virtual channel more approaching to the real distribution of the residual difference data was validated.