Abstract: The generalized Maxwell model, which describes stressrelaxation modulus, is usually used for analyzing the rheologicalcharacteristics of viscoelastic materials. While data of relaxation modulusobtained from experiments are usually expressed as Kohlrausch-William-Watts(KWW) function, which is in an exponent-spread form. In the paper, thefitting of KWW function to the generalized Maxwell model is turnedinto the equality of two matrixes, which is equivalent to make the1-norm of the matrix difference infinitely small. Minimumvalue of the 1-norm is achieved by introducing the generalized inverse ofmatrix. At last, taking the minimum value of the 1-norm as the objectivefunction, and relaxation time as the constraint condition, a simplex methodis used to optimize the minimum value of the 1-norm. A new computationalmethod for fitting of KWW function to the generalized Maxwell modulus by means of MATLAB software is proposed.