Abstract: In order to proceed comprehensive evaluation of complicated multi-factors system with fuzzness rationally, a new mathematical model is established about multi- factors and multistage fuzzy comprehensive evaluation by combining fuzzy matrix with fuzzy integral. Then a method is put forward for determining the single-factor evaluation matrix and the weight of factor, finally, a reasonable comprehensive evaluation procedure is given for laboratory. The theory and the way can widely be applied to similar multi-factors comprehensive evaluation system with fuzziness