Abstract: A three dimensional elastic stress analysis method is provided for air cooled turbine blades of orthotropic material with contoured passages.The analytical results are presented for a real air cooled turbine blade.The sectional linear and nonlinear assumptions are adopted to divide a blade into elements and to form the geometrical and mechanical models,the coordinate transformation is employed to set up an elastic matrix of the elements,and the sectional linear interpolation is used to consider the effect of the temperature on the blade metal,so as to calculate the directionally solidified air cooled turbine blades with complicated contoured passages and the high temperature differences between the inner and outer walls.The method and the program have been verified and the accuracy could meet the requirements of engineering.