Using observational and reanalysis data, the variaton of the Tibetan Plateau Summer Monsoon (TPSM) and its relationship with the India Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM) are investigated by the correlation analysis and the composite analysis. Results show that the TPSM in 2008 is earlier and stronger than normal. The most significant period of the intraseasonal oscillation in the TPSM is biweekly, similar to those of all ISM rainfall and the EASM index. When the TPSM is strong (weak), the precipitation in all India and North China tends to be less (more) than normal. During the active phase of the TPSM, the position of the Indian－Burma monsoon trough is to the east and north of its normal place, so that the moisture transportation in front of the trough is of benefit to the rainfall in the southeast of the Tibetan Plateau, but the ISM breaks for the influence of the high ridge over the Indian continent. Meanwhile, since the Western Pacific Subtropical High (WPSH) is to the east and south of its usual location, the EASM precipitation concentrates in East China. On the contrary, when the TPSM is weaker, with the WPSH expanding westward and shifting northward, the lower southwesterly jet shifts northward, thus both the southwesterly moisture transportation from lower latitudes and the southeasterly moisture transportation from the south edge of the WPSH contribute to the more precipitation in North China. It is also shown that the TPSM oscillation related to diabatic heating modulates the behavior of the South Asia high to a considerable degree.