Anew procedure of cross-ventilation characteristic test of inflow opening based on local dynamic similarity model has been proposed. When cross-ventilation characteristic test of actual size opening is carried out by the traditional means, there is fear that it is made an incorrect evaluation by the blockage effect to cross-section of wind tunnel. Because an opening was set parallel to floor of wind tunnel, it could avoid the influence of blockage effect by the method in this paper. The relational equation between the dimensionless indoor pressure and discharge coefficient was derived from the characteristic tests of various openings by this method. The database of primary parameters for the equation of various openings was made out.