The biometrics of iris is a very accurate authentication method. The biometrics of iris can recognize and identify a person for shortly. But the image of iris is changed by transformation of body in the life. The existing iris authentication system has problem that can be mis-recognized. In this paper, we proposed and implemented Renewable Iris Authentication Algorithm(RIAA) for biometrics in authentication system. This algorithm tries to present a new way to people identification, we show contour line when shift take photograph in regular side. Namely, it generate iris code based on boundary of projection or submergence side and compared to original, so that it describes iris identification method to people identification.