Abstract: The characteristics and changes of water vapor transport and the thermodynamic characteristics of the local, eastward, northeastward, and southward types from various vortex sources (subregions 1 and 2) in the western Sichuan Plateau are thoroughly examined through observation and diagnosis. The ECMWF Reanalysis-interim data from June to August of 1989–2018, based on the new definition of the Jiulong vortex (JLV) of the Southwest China vortex, were examined to conduct this investigation. The results demonstrate the following: (1) The water vapor primarily arises from the Indian Ocean during summer. Under the action of multiple systems, a southwestward transport of water vapor is observed in the local, eastward, and northeastward types, whereas a northwestward transport of water vapor is observed in the southward type. The convergence of water vapor in the generation region is strengthened via the formation of the JLV, at the end of which the moving (eastward, northeastward, southward) type exhibits an anomalous convergence of water vapor flux downstream of the corresponding moving direction. (2) The JLV region primarily involves heat consumption. The local type may not have sufficient supplies and requires a substantial amount of heat, which may be one of the factors leading to its demise. Water vapor is consumed at the lower level and grows at the higher level at birth, but after development, it is consumed throughout the layer. Because of the complex (simple) effect of the underlying surface and circulation associated with subregion 1 (subregion 2), the apparent heat source and apparent water vapor sinks exhibit diverse (single) vertical distributions, with multiple (one) extreme centers. the polar center of the apparent heat source is higher than the polar center of the apparent water vapor sink due to radiative cooling and vertical transport of small-scale vortex. (3) The large value area of the apparent heat source and apparent water vapor sink of JLV are mainly located in the northeast of the low vortex, which corresponds to the strong convection area of the JLV, and the apparent water vapor sink is stronger than the apparent heat source, which corresponds to the strong nocturnal. The intensity of the distribution and variation of the apparent heat source and apparent water vapor sink of the moving type are typically stronger than those of the local type. Among them, the northeastward type and southward type of subregion 1 always maintain a strong distribution of the apparent heat source and apparent water vapor sink , which is in considerable contrast to that observed in local and eastward types. In Subregion 2, the moving type and the local type differ slightly at birth, and after development the northeastward type is greatly improved. (4) The demise of the local type is first manifested as the weakening of the apparent water vapor sink at the periphery of the low vortex, while the eastward and northeastward types expand and strengthen in the direction of movement. There is a large heat source system on the southwest side of the southward type, which may be an external forcing factor for its southward migration. In conclusion, the abnormal changes in regional and environmental water vapor and atmospheric thermodynamic conditions are strongly associated with the evolution of the JLV; such changes could be the main reasons for the formation, extinction, development, and movement of the JLV.