With the rapid progress of urbanization, urban construction has brought about the shortage of land resources, which makes more and more cities develop towards high-rise, three-dimensional and intelligent development. The optimal layout of three-dimensional space of urban buildings is the basic condition for the intensive development of the city. In view of the current deficiencies in the three-dimensional space layout of urban buildings at present, this study constructs an evaluation system of the three-dimensional space layout of urban buildings. Taking the coastal zone of Xiamen Island as the research area, based on multi-source and multi-spatial resolution remote sensing image data, evaluate the current situation of the three-dimensional spatial structure of the architectural complex in the coastal area of Xiamen Island from the three perspectives of architectural landscape, thermal environment and visual effect. And summarized the urban tfhree-dimensional spatial layout optimization development mode. Finally, from the three perspectives of architectural landscape, thermal environment and visual effects, suggestions for the optimization of the three-dimensional space layout of the coastal zone of Xiamen Island are proposed. The evaluation results of three-dimensional space layout show that: (1) From the perspective of architectural landscape, the relationship between different functional buildings and floor area ratio is as follows: commercial area have the highest floor area ratio, followed by commercial housing residential areas; cultural and educational areas cover a wide area and have low building density; civilian residential areas have the lowest floor area ratios but have high building density; (2) From the perspective of thermal environment, considering the temperature factor, excessive building density and too many building floors will cause higher temperatures; (3) From the perspective of visual effect, the study area has a broad visual space, which is in a sharp contrast with the skyline with the mountain as the background. In addition, it is proposed to improve the floor area ratio of low-rise buildings, rationally arrange the floor area ratio of middle and high-rise buildings, and design diversification of building forms and highlight the hierarchy of skyline foreground, middle scene and background, so as to optimize the three-dimensional spatial layout of of the urbanl buildings of Xiamen Island. This study can provide basic data support and technical support for three-dimensional space layout optimization of the urban buildings in the coastal zone of Xiamen Island, and provide decision support for government departments such as urban land resource planning. It is of great significance for rational utilization of the three-dimensional space and landscape optimization of the urban buildings. It also provides new theoretical basis and reference for the study of sustainable development of other cities in our country.