The JRA-25 reanalysis dataset provided by the Japan Meteorological Agency(JMA) was utilized to investigate the spatiotemporal characteristics of surface sensible heating over the Tibetan Plateau(TP) in boreal spring, as well as their effect on the onset of the Indian summer monsoon(ISM). The EOF results show that the most evident interannual variability of sensible heat occurs over the central-western TP in spring; this is primarily attributed to the interannual variability of the land-air temperature difference in situ. This is demonstrated by statistical analysis, which shows that the ISM builds up early(late) with strong(weak) spring sensible heat over the central-western TP, which is not significantly correlated with ENSO events. In fact, the spring sensible heat over the central-western TP could alter the ISM onset time by changing the meridional thermal structure in both the upper and lower troposphere over the ISM region. When the spring sensible heat over the central-western TP is stronger, local ascent is enhanced followed by descent to the west of the TP, which is to the north of the ISM region. Thus, the anomalous warming induced by the adiabatic process could accelerate the seasonal transition of the meridional mean temperature gradient in the middle and upper troposphere from winter to summer. Meanwhile, the subsidence anomaly to the north of the ISM region could prevent rainfall development in situ causing the land surface temperature to increase. Thereafter, the strengthened diabatic heating of the land leads to the warm center in the lower troposphere, increasing the land-sea thermal contrast in the ISM region. As a result, the anomalous warming in both the upper and lower troposphere contributes to the early onset of the ISM under the influence of the stronger spring sensible heat over the central-western TP.