【Objective】Tea (Camellia sinensis L. Kuntze) is a perennial plant widely cultivated in South China. As a high N-demanding cash crop, tea has been applied widely with synthetic N fertilizers to increase its yield. However, application of excessive synthetic N fertilizers in tea gardens might affect chemical properties of the soils and their nutrient supply to tea plants; in addition, it may have some negative impacts on growth of the tea plants and the environment. Although researchers in China have been doing some experiments simulating application of synthetic N fertilizers in tea gardens, so far none of them has been doing to systematically or quantitatively evaluate responses of tea soils to application of synthetic N fertilizer. Through meta-analysis, this paper tries to evaluate quantitatively how application of synthetic N fertilizers affect basic chemical properties and nutrient supply of the soil, and loss of reactive N to the environment. 【Method】In this paper, meta-analysis was done of the 17 papers published in the literature during 2004-2016 involving 15 indicesin 246items of data and records. 【Result】Results indicated that application of synthetic N fertilizers lowered soil pH significantly by 0.20 units on average. In soils of tea gardens different in tea tree species, application of synthetic N fertilizers significantly decreased soil pH and no significant difference was found between subgroups. Soil acidification in the tea gardens was expedited because the application accelerated nitrification process, triggered loss of base cations, and damaged the soil buffering system, thus resulting H+ release. As a whole, application of synthetic N fertilizers had on significant impact on soil organic carbon (SOC). However, it did increase SOC by 15% (7%~24%) in tea gardens of green tea and by nil in tea gardens of oolong tea. Application of synthetic N fertilizers increased soil total N by 18% (10%~27%), and soil dissolved inorganic N availability by 172% (127%~236%). The responses of soil DIN, NH₄⁺-N and NO₃⁻-N concentrations to application of synthetic N fertilizers varied between soils with different tea trees. DIN and NH₄⁺-N concentrations were significantly higher in tea gardens of oolong tea than in those of green tea. NO₃⁻-Nconcentration was significantly higher in tea garden of black tea and oolong tea, but remained almost unchanged in those of green tea. Soil phosphorus and potassium was not much affected in the tea gardens of China. In addition, the application lowered soil calcium and magnesium content by 23% (-30%~-16%) and 37%(-48%~-24%), respectively, but raised soil aluminum accumulated by 54% (38%~69%) in the soils. Besides accelerating microbial nitrification processes, the application also stimulated losses of soil reactive N from the soil to the environment as a result of its increasing N₂O emission and inorganic N leaching by 292% (140%~575%) and 127% (55%~206%), respectively, or more specifically leaching loss of soil NH₄⁺-N and NO₃⁻-N by 422% (280%~617%) and 92% (31%~161%). The stimulated loss of reactive N might pose a great threat to the environmental and ecological safety of the tea planted areas, even the whole country. 【Conclusion】To sum up, application of synthetic N fertilizers significantly enhance the supply of total N and available N in the tea garden soils in China. However, it also causes serious environmental problems in the areas and the whole country by accelerating soil acidification, leaching loss of massive base cations, accumulation of toxic aluminum and loss of reactive N through emission of N₂O and leaching, thus affecting sustainable development of tea gardens. Most of the studies so far done have been conducted on a small scale (greenhouse or pots) both in area and time. It is advisable to have some long-term field studies so as to evaluate accurately responses of the tea garden ecosystems in key processes and provide some theoretical and practical bases for understanding N recycling processes in the tea garden ecosystem and scientific N management for sustainable development of tea cultivation in China.