Abstract: The characteristics of the interdecadal variability in the differences between surface temperature (T_s) and surface air temperature (T_a) are analyzed, using daily-observed surface temperature and surface air temperature data from 1960 to 2006. Analysis results show that there is a clear interdecadal variability in T_s-T_a in Southeast and Northwest China. Before the late 1970s, the T_s-T_a anomalies were mostly positive in Southeast China, but they mostly became negative after this period. In contrast, in Northwest China, the T_s-T_a anomalies were mostly negative in spring and summer before the late 1970s, but became largely positive after this time. The opposite trend can be seen in the variability of T_s-T_a in Northwest China in the winter. However, in the autumn in Northwest China, the interdecadal variability of T_s-T_a was not as clear as during the other seasons. The analyzed results of T_s and T_a over the study period show that their contributions to interdecadal variability of in T_s-T_a differed between different seasons.