Abstract: The scattering of SH-wave by an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated and the solution of dynamic stress concentration factor is given by Green's function, complex function method. Firstly, the space can be divided into up-and-down parts along the interface. In the lower half space, a suitable Green's function for the present problem were constructed, which is the essential solution of displacement field for an elastic half space with a semicylindrical hill of cylindrical elastic inclusion while bearing out-plane harmonic line source load at horizontal surface. Thereby the semicircular disconnected curve can be constructed when the two parts are bonded which is continuous in the interface loading the undetermined anti- plane forces on the horizontal surfaces. And the expressions of displacement field and stress field were obtained under this situation. Finally, some examples and results of dynamic stress concentration factor were given, and the influences by the cylindrical inclusion and the difference parameters of the two mediators were discussed.