The dispersed relaxation time spectra of materials were evaluated direct from the conventional experimental stress—relaxation curves by means of data—operation instead of overlaborate function—analysis procedure．The principal relaxation time τ0 was determined from the single Maxwell model．and another relaxation times were appointed at about 10-2 τ0 10-1 τ0

101 τ0 103 τ0 The stress-relaxation equation was expressed in the form as a model with 5 parameters，and the spectrum intensities ai (or Ai) were determined from the linear multielement regression and the least square method．The relaxation curves of NR (nature rubber) samples at different temperatures were handled，a comparison of the calculated data with experimental curves shows good agreement．The obtained spectra represent the activation of relaxation process due to heating，and that the spectrum intensities are stronger in short—time region，means that the main micro-scopic relaxation depends on the motion of segments，but not of molecular chain．