屋顶绿化是一种不占用地面土地资源，适于城市绿化建设的新型绿化形式。本文以北京屋顶绿化为研究对象，介绍了植物应用现状和空间分布特征，分析了区系组成特征及植物功能属性，从供给功能、调节功能、支持功能和文化功能四个方面探讨了由植物功能属性延伸出的屋顶绿化植物生态服务功能。结果发现：①北京屋顶绿化植物大多耐寒、耐热、耐寒且抗风，并具有叶小、植株矮小、根系浅、生长速度偏快、繁殖途径多样的特点；②屋顶绿化植物中，木犀科（Oleaceae）的日本女贞（Ligustrum japonicum Thunb.）和蔷薇科（Rosaceae）的海棠（Malus spectabilis (Ait.) Borkh.）综合生态服务功能水平高，旋花科（Convolvulaceae）的菟丝子（Cuscuta chinensis Lam.）和苋科（Amaranthaceae）的凹头苋（Amaranthus lividus）综合生态服务水平低，五加科（Araliaceae）植物综合生态服务功能水平最高，伞形科（Umbelliferae）和苋科植物综合生态服务功能水平低。探究北京屋顶绿化植物各项功能属性所反映的生态服务功能既可以为北京屋顶绿化的植物选择提供实际参考价值，又对我国城市屋顶绿化生态建设的设计具有一定理论意义。

Roof greening is a new type of greening which occupies few land resources and is suitable for urban greening construction. Using roof greening in Beijing as a case, this paper introduced the present situation of roof greening types and taxonomic characteristics, and analyzed plant floristic composition and functional traits. Finally, the ecosystem services of roof greening plants were discussed in four aspects: provisioning services, regulating services, support services, and cultural services. Results revealed that most of the roof greening plants have drought resistance, heat endurance, cold tolerance and wind resistance. Besides, they also have the characteristics of small leaves, short plants, shallow roots, fast growth speed and diverse reproductive routes. Among the roof greening plants in Beijing, the ecosystem service level of Ligustrum japonicum Thunb and Malus spectabilis (Ait.) Borkh is high, and the esosystem service levels of Cuscuta chinensis Lam and Amaranthus lividus are low. The ecosystem service level of Araliaceae is high, and the ecosystem service levels of Umbelliferae and Amaranthaceae are low. Exploring the ecosystem services reflected by various functional attributes of Beijing roof greening plants can not only provide practical reference for the selection of green roof plants in Beijing, but also have a certain theoretical significance for the design of urban green roof ecological construction in China.