Xiong'an New Area, as a newly established area in China, is a major goal of planning to build a new, green, eco-friendly and livable urban area. In recent years, the urbanization process of Xiong'an New Area has accelerated, the urban landscape has changed greatly, and the urban heat island effect has become more and more serious. The blue-green space in the urban ecosystem can provide the temperature regulation function to improve urban thermal environment. Based on Landsat remote sensing data and land use data, this paper analyzed the cooling benefits of ecological patches and simulated the reducing heat function of the ecosystem in Xiong'an New Area. The results showed that:(1) in Xiong'an New Area, the cooling distance of lakes is the largest, which is 350 meters, and the cooling range is 1.29℃. In the green land, the cooling distance of woodlands and gardens is the largest, which is 300 meters, and the cooling range is 0.79℃ and 0.62℃. (2) There was a certain correlation between different ecological patch temperatures and landscape pattern indexes, among which area (AERA), perimeter (PERIM), perimeter area ratio (PARA) and Euclidean nearest neighbor distance (ENN) index were strongly correlated. differently ecological patch types have different thresholds, within which the temperature decreases. In the process of urban blue-green space planning, the cooling threshold of each ecological patch can be referred to for construction. (3) The heat reduction of Xiong'an New Area is between 0.4℃ and 5.63℃. The maximum reducing heat function of areas mainly distributed in the Baiyang Lake, where the lakes play the most important role and followed by the part of woodland and grassland in built-up area. The reducing heat ability of the river channels is relatively low, and the weakest is a few grasslands and woodlands that are distributed in the northern built-up area of Xiong'an New Area.