Abstract: In July 2018,taking plantations of Acacia crassicarpa A.Cunn.ex Benth.,A.melanoxylon R.Br.,A.cincinnata F.Muell.,A.auriculiformis A.Cunn.ex Benth.,and A.mangium Willd.as research objects in Zhangzhou City of Fujian Province,the homeostasis characteristics of N,P,K and C:N,C:P,C:K and N:P of their mature leaves were studied,in order to reveal the ecological adaptation strategies of different Acacia species.The results show that:there were differences in the internal stability index of leaf elements of different Acacia species,except for the N homeostasis index of A.melanoxylon R.Br.,the H_N of the other four Acacia species belonged to the sensitive type,and the P and K homeostasis indices of the five Acacia species were sensitive.The stoichiometric ratio of elements was significantly higher than the elemental content,and the C:N stability indices of Acacia species were all steady-state,The H_C:P,H_C:K,and H_N:P of Acacia species generally showed weakly stable or steady state types (except for H_C:P of A.auriculiformis A.Cunn.ex Benth.,H_C:K of A.cincinnata F.Muell.and H_N:P of A.mangium Willd.).In conclusion,Acacia crassicarpa A.Cunn.ex Benth.had higher H_C:P and H_C:K,A.melanoxylon R.Br.had higher H_N and H_N:P,and A.cincinnata F.Muell.had higher H_P and H_C:N,indicating that different Acacia species had different adaptability to the external environment,and Acacia species with higher homeostasis had stronger adaptability to the corresponding soil nutrient variation.