According to the hypothesis of plain section and the equation of moment versus curvature of R.C section, the elastic-plastic response of pressed continuous beams is analyzed with CDC-method. The correlation equation of support reaction increment and displacement increment is induced through the relation of moment increment and curvature increment,and the adjustment value of support reaction increment of continuous beams is determined by solution of linear equation systems,which provides a rule the support reaction to follow. It can roundly and quantificationally display the moment redistribution behavior of continuous beams. A case of 4 spans continuous beam shows a high calculation rate and precision of this method.