We suggest a new algorithm for relaxation time spectrum, which is based on the power series approximation of dynamic modulus and relaxation time spectrum. Through the regression of dynamic modulus as a polynomial of the logarithm of frequency, the method converts the coefficients of the modulus to those of relaxation time spectrum. The algorithm provides relaxation time spectrum as stable as regularization method. (C) 2013 The Society of Rheology. [http://dx.doi.org/10.1122/1.4789787]