In order to alleviate the urban heat island effect, absorb harmful gases, reduce temperature, and increase humidity, a method of energy conservation optimization and numerical simulation of urban green space landscape pattern is proposed. Based on the theory of landscape ecology, green wedge, green belt, green road, park, and other types of green space with different ecological functions are designed in Shenyang, and an optimization scheme of urban green space network spatial structure of “four belts, three rings, seven wedges, and network connection” is formed. Combined with remote sensing (RS) and geographic information system (GIS) spatial analysis technology, the atmospheric environment effect under the influence of green space landscape optimization pattern in summer based on computational fluid dynamics (CFD) numerical simulation technology is analyzed, and the corresponding optimization strategies of urban green space planning are put forward. The simulation results show that in the bottom wind speed field of 1.5 m, the area ratio of 0∼0.375 m/s wind speed is 15.87%, and the area ratio of 2.625∼3 m/s wind speed is 32.06%. In the bottom concentration field of 1.5 m, the spatial diffusion capacity of SO2 pollutants is enhanced, and the concentration of pollutants is relatively low. The area ratio of SO2 concentration is 10.06% in the range of 0.1292∼0.1551 mg/m3, and the area ratio of SO2 concentration is 68.08% in the range of 0∼0.05169 mg/m3. It is concluded that the spatial diffusion of wind speed, SO2, and temperature is closely related to the urban spatial layout. The optimal spatial layout of urban green space can effectively alleviate the urban heat island effect, promote the spatial diffusion of SO2, and better form the urban ventilation corridor. The research on atmospheric environmental effects of urban green space based on CFD can effectively simulate and evaluate the optimization measures and conceptual design of urban green space system planning, and also provide new ideas for the quantitative planning of urban green space system.