The characteristics of the aerodynamic damping of a row of casacded blades in transonic flow are examined by the "one blade oscillation method" we developed formerly. Concerning the aerodynamic interaction between neighbouring blades, we uncovered some hidden aspects in the overall results obtained by the "all blades oscillation method" and it is made clear that there exist obvious differences between the aerodynamic interactions in transonic compressible flow and incompressible flow. In the present report, we treated a case of turbine cascade with a high stagger angle but a low turning angle. In the next report, we will treat the case of a transonic turbine cascade of high turning angle with practical blades.