【Objective】Soil quality problems often arise in the process of greenhouse agriculture pursuing economic benefits. There are also signs of soil quality changes in the Tibet Plateau greenhouse land, and the regional differentiation pattern of soil quality changes in the Lhasa Valley. The Lhasa Valley is the main distribution area of greenhouse plots on the Tibet Plateau. Nevertheless, there is limited research that integrates the physical and chemical properties of its soil to reflect overall soil quality changes in the facility farmland with a comprehensive index, and the overall soil quality changes and their regional differentiation patterns are not yet clear. 【Method】Taking the arable land soil samples as the references, this study collected 240 soil samples of greenhouse land and 112 soil samples of arable land. The texture, pH value, water-soluble total salt content, organic matter, total nitrogen, alkali-hydro nitrogen, total phosphorus, available phosphorus, total potassium, available potassium, and soil heavy metals elements (Cr, Ni, Cu, Zn, Pb, Cd, As, Hg) were determined. The comprehensive soil quality index and factor detector methods were used to study the soil quality changes and spatial differentiation characteristics of the greenhouse land soil in Lhasa Valley, and the main factors of soil quality changes in the greenhouse land soil were identified.【Result】The comprehensive soil quality indices of the Lhasa valley greenhouse land and the arable land soil were 0.36, and 0.43, respectively. The soil quality grades of 80% of both samples were distributed in V～III. The soil quality of the greenhouse land was relatively high on the sunny slopes within 930 m from the river at an altitude of 3, 700～3, 750 m in the area. Secondly, there were spatial differences in the degree of soil quality variation in the study area. The SQI of the greenhouse land decreased by 16.28% on average compared to that of the larger field farmland. Among them, soil quality in the Doilungdeqen county decreased most significantly, with an average decrease of 74.46%. At different depths, soil quality decreased most significantly in the range of 0～10 cm, in which the average decline was 6.5%, and the highest percentage of declining sample plots, at 66.67. Thirdly, there was spatial heterogeneity in soil quality changes in the greenhouse land affected by altitude and slope direction. With the increase of elevation and the change of soil quality from sunny slope to shady slope, the change of soil quality in the agricultural land facilities showed a significant trend of increase. Finally, analysis of the soil quality change factors in greenhouse land found that the soil quality change in the whole region was generally affected by changes in salt content, available potassium and cadmium content, and the explanatory power of all three could reach 20%.【Conclusion】Under the changing influence of salt accumulation, available potassium and cadmium content changes, the overall soil quality of the study area's greenhouse land showing a decreasing trend and varied significantly in different regions. This could provide a theoretical basis for the layout and development of greenhouse agriculture in the region.