Abstract: The prediction ability of the simplified Acierno-typeconstitutive equation is examined in the present paper. The thixotropy-looptests of an LDPE(Q200) melt are predicted by the simplified Aciernoequation, and the differences between the model and the variant Huang modelin the descriptions and the predictions of the thixotropy-loop tests arecompared. It is shown that the deviations of the predictions bythe simplified Acierno equation from the experiments are smaller than those obtained by the variant Huang model under the same calculationconditions, although only partial descriptions of the thixotropy-loop testsof the melt by the simplified Acierno model agree with theexperiments. The constitution of the simplified Acierno equation is morereasonable than that of the variant Huang model.