Several important factors, including Gaussian blurring,finite imaging region, and discrete computation, were considered to study the stability of moment invariants in practical application. The effect and rules of each factor to the moment invariants were investigated. The stability of moment invariant on the discrete data case was analyzed. The experiments show that it is possible to recognize the blurred and rotated images accurately by the suggested invariants. All these researches will provide important theoretical and experimental foundations for practical imaging recognition systems.