Abstract: In order to predict the blade force defect a new model is proposed which is based on the analysis of the deflection of the blade force in boundary layer due to the secondary flows in cascade both with and without tip clearance. It is assumedthat the scalar product of blade force defect and mainstream velocity is proportionalto the work done by the cascade secondary flow drag and can be expressedas equation(16) in the present paper. This equation approaches to the relationsuggested by Mellor et al. as the lift coefficient value of the blade is very low. A method using the values of blade force defect in boundary layer is pre- sented to estimate the compressor efficiency. The end wall boundary layer thicknessesare calculated and the blockage in meridional plane is obtained for two axial compressors and an inlet guide vane. The efficiency of a compressor is also estimated. The analysis indicates that reasonable results can be obtained by the use of this method.