Rice is one of the important food crops. Paddy fields have the specifically underlying surface due to irrigation-Cold-Humid Effect, which leads to direct influence on the regional climate. This study retrieved the land surface temperature based on thermal infrared data of Landsat8 TIRS, and depicted the spatial pattern of thermal environment for the paddy-planting core region in the Sanjiang Plain. From the perspective of pattern and process of Landscape Ecology theory, this study quantified the impact of paddy field landscape pattern on the spatial differentiation of the internal land surface temperature, and the influenced range and degree on the local thermal environments. The result showed that (1) the land surface temperature had the spatial polarization feature, which matched with spatial distribution of paddy fields and dry croplands. The difference of averaged land surface temperature between paddy fields and dry croplands was -7.8℃. (2) The averaged land surface temperature of paddy fields was negatively correlated with the size and connectivity of paddy fields, and positively correlated with their shape. (3) The cooling distances of paddy fields were between 60 m and 300 m, and the cooling degree was between 0.05 ℃ and 9.7 ℃. The internal temperature of paddy fields had the most influential effect to the cooling distance and degree, which were negatively correlated. The size and connectivity of paddy fields were positively correlated with the cooling distance and degree. The shape of paddy field had the least cooling influence. In the view of the interaction between the paddy field landscape and local thermal environment, this study emphasized the importance of the nonlinear transverse transmission of matter and energy in the study of the climate effects of agricultural irrigation.