In this study, the two-channel and differential dielectric spectroscopy (TD-DES) technique has been applied to study different degrees of oxidative degradation for two series of simulated oxidized lubricating oils at low temperatures ranging from 20 degrees C to-55 degrees C. The deep oxidation, general oxidation, nitration, and sulfation products of the degraded lubricating oil were precisely identified by the Fourier transform infrared spectroscopy (FT-IR) and increased with the level of oxidation, which agreed well with the TD-DES data at room temperature (20 degrees C). For the severely degraded lubricating oil, the TD-DES real and imaginary data and relaxation characteristic changes from 20 degrees C to-55 degrees C were dramatically reduced; the interlacing characteristics of Cole-Cole plots at low temperatures could be ascribed to the formation of high-molecular-weight products during the oxidative degradation process. It was found that the two-dimensional (2D) synchronous and asynchronous dielectric spectroscopy were able to qualitatively describe the degrees of simulated oxidative degradation and the formation of highly oxidized products, as well as to explain the polarization relaxation mechanism of degraded lubricating oil. The partial least-squares (PLS) and multilinear-PLS (N-PLS) regression results indicated that 2D synchronous and asynchronous dielectric spectroscopy could better predict the FT-IR deep oxidation, general oxidation, nitration, and sulfation peak areas than TD-DES real data at 20 degrees C with regard to lower root-mean-square error of cross-validation (RMSECV), better correlation coefficients (R), and smaller predicted errors.