Abstract: Using daily temperature extracted from the ERA-Interim reanalysis data during 1979-2014 and the temperature lapse rate interpolation method, the occurrence frequencies of two types of tropopause (the tropical tropopause and the polar tropopause) in the Northern Hemisphere are calculated. Seasonal variations of the occurrence frequencies of the two types of tropopause over the Tibetan Plateau and their differences to that in the same latitudes are demonstrated and discussed first. The relationships between the occurrence frequencies of the two types of tropopause and upper air temperature over the Tibetan Plateau are explored. The results are as follows:1) The occurrence frequencies of the two types of tropopause calculated using the reanalysis data and temperature lapse rate interpolation method are consistent with their climatological variations observed over the Tibetan Plateau. Differences in the tropical tropopause occurrence frequency between cold and warm seasons are insignificant with high frequency all year round. However, differences in the polar tropopause occurrence frequency between cold and warm seasons are obvious with very low occurrence frequency in July and August. The tropical tropopause occurrence frequency derived from the ERA-Interim reanalysis dataset is more reliable than the polar tropopause frequency. 2) During warm (cold) season, the tropical tropopause occurrence frequency increases (decreases), while the seasonal variation of the polar tropopause occurrence frequency is opposite. Compared with that in the same latitudes, the tropical (polar) tropopause occurrence frequency is less (more) frequent in winter but more (less) frequent in other seasons. The gradients in the occurrence frequencies of the two types of tropopause over the Tibetan Plateau are more distinct, indicating that the tropopause over the Tibetan Plateau is more likely to break. 3) The seasonal and interannual variations of the occurrence frequencies of the two types of tropopause are closely linked with temperature over the Tibetan Plateau. When the temperature in the upper troposphere (in the lower stratosphere) over the Tibetan Plateau increases (decreases), the tropical tropopause occurrence frequency increases and the polar tropopause occurrence frequency decreases accordingly, and vice versa.