The daily observation data set of the National Meteorological Station of China from 1991 to 2020 and the urban green space area data of China in 2020 were used to analyze the effects of extreme climate on major urban gardens in China with the percentile method and GIS spatial analysis technology to study the risks of urban gardens suffering from extreme climate under the background of global climate changes. The results showed that the high-risk areas affected by extreme low temperatures were located in the northern and high-altitude areas of China. High risk areas of extreme high temperature generally occurred in eastern cities with rapid urbanization. The high-risk areas of heavy precipitation were basically consistent with the distribution of rainfall belts in China， mainly located in central and southern China， with average precipitation of above 30 mm. Shigatse and Naqu in Tibet， and the northern and eastern coastal areas of China are high risk areas of gales. Urban green space in the Yunnan-Guizhou Plateau， the middle and lower reaches of the Yangtze River， parts of North and Northeast China are vulnerable to extreme drought. Designing urban gardens in the future needs to combine the characteristics of local extreme climate， improve tree species and planting structures， and enhance the adaptability of ecological systems such as landscape architecture to climate changes.