Abstract: An analysis using complex exponential series is developed for the problem of a crack on the boundary between two dissimilar materials.The eigenvalues and the relations among the complex constants are determined by the use of crack face boundary conditions and the continuity conditions at the interface.From these results the stress and displacement fields and the stress intensity factors have been determined,the stress function used by Lin1 and by Lin and Mar2 are modified and the solution reduces to results obtained by Williams6 and by Sih and Rice3,4.A singular element based on the results is used to develop a finite element analysis of finite tension sheet with a central crack on a straight interface boundary.