The amount of falling flowers of trees in urban greening is increasing. Because falling flowers are rich in nutrients, the study on the decomposition and nutrient release characteristics of falling flowers can provide scientific basis for the use of falling flowers as fertilizer materials and the preparation of biomass organic fertilizer and other agricultural reuse. Taking Cerasus sp., Malus spectabilis, Magnolia denudata, Magnolia liliflora, Amygdalus persica, Prunus cerasiferaⅠ, Prunus cerasiferaⅡ, Michelia figo, Cercis chinensis, Prunus mume, Ginkgo biloba, and Koelreuteria paniculate as the research object, the falling flowers decomposition simulation experiments were carried out in laboratory. The results show that: (1)The crude protein content is higher in flowers of Amygdalus persica and Magnolia denudate(251.44-274.94 mg/g)(P<0.05).The lignin content is higher in flowers of Cercis chinensis and Ginkgo biloba (47.35-49.95 μg/g) and the N content is higher in flowers of Amygdalus persica and Magnolia denudate (40.23-43.99 mg/g), but the P content is higher in flowers of Amygdalus persica and Magnolia denudate (1.37-1.58 mg/g).The K content is higher in flowers of Prunus cerasiferaⅠ, Prunus cerasiferaⅡ, and Magnolia denudate (4.53-4.72 mg/g), while the content of Cu is higher in flowers of Magnolia denudate (22.74 μg/g). The content of Zn is higher in flowers of Prunus cerasiferaⅡ (249.06 μg/g) and the content of Fe is higher in flowers of Cercis chinensis, Cerasus sp., Prunus cerasiferaⅡ, Prunus mume, Malus spectabilis and Amygdalus persica (85.81-118.34 μg/g). The Mn content is higher in flowers of Prunus mume, Cerasus sp., Amygdalus persica and Malus spectabilis (24.09-25.71 μg/g). (2) Among the 12 species of falling flowers, except that the decomposition of Ginkgo biloba is a little slower (the turnover period as 1.12 a), the decompositions of other falling flowers are faster (the turnover period as 1.00-1.05 a). (3) Compared with the decomposition rate, the nutrients release rate of falling flowers is as following: N in Cerasus sp., Malus spectabilis, Magnolia liliflora, Prunus cerasiferaⅠ, Michelia figo and Cercis chinensis show overspeed release state, while in other falling flowers show slow release state. P in Magnolia denudate, Amygdalus persica, Prunus cerasiferaⅡ, Cercis chinensis and Ginkgo biloba falling flowers show overspeed release state, while in other falling flowers show slow release state; K, except in Cercis chinensis falling flowers, show slow release state. (4) The correlation analysis indicates that the higher crude protein, N, P and K contents in falling flowers can accelerate the decomposition of falling flowers, while the higher lignin content, lignin/N and N/P in falling flowers can slow down the decomposition of falling flowers. The above results will lay a theoretical foundation for the resourceful utilization of falling flowers.