The specialshaped cross connecting piece can be assembled to be a kind of frame type connector used to inlaid glass.Because of its structure,this connecting piece is difficult in clamping and alignment during processing.The structure and the processing difficulty were analyzed.The method that the photoelectric edge detector was used to touch the tool setting points of the specialshaped cross connecting piece which was clamped in any angle,then NC macro program and the program operation “singlesegment” function of NC machine were combined to ensure the workpiece center was proposed.The experiments prove that this method can be used to solve the alignment operation problem properly and effectively.