Abstract: With the conventional meteorological observation data, NCEP and ERA-interim reanalysis data, the thermal convective precipitation in Nagqu City from June to August 2017~2019 is statistically analyzed. The results show that in the past three years, there have been 27 days of thermal convective weather, and the most concentrated period of thermal converction precipitation in the afternoon is from 15 to 17 o'clock. When thermal convection weather occurred, the maximum temperature (Tmax) and maximum ground temperature reached at least 14.2℃and 32℃ respectively. The daily maximum temperature and maximum surface temperature were 10.4℃ and 37.3℃ higher than those at 8:00 a.m. Considering the convection temperature (Tg), the frequency of thermal convection is the highest while the value of Tmax-Tg is between 1.5℃ and 5.5℃, and the probability of thermal convection is 0 when the value is less than 1℃ or greater than 8℃. Therefore, it is not that the larger the Tmax-Tg value is, the greater the probability of heat convection occurs. In terms of water vapor conditions, the average wet layer at 8:00 a.m. is below 460hPa, with the characteristics of being dry at the top and wet at the bottom. By correcting the Tlog-P curve, the CAPE value should reach at least 800J·Kg⁻¹ when the thermal convection occurs. From the synthetic ananlysis of individual cases, it is concluded that Naqu City is in a state of high pressure control or clear sky with few clouds before the convection weather occurs, and there is convergence and upward movement in the afternoon. The convergence and upward movement of the lower level will result in the condensation of surrounding water vapor. The source of water vapor whether is derived from advection transport or surface evaporation remains to be further studied.