Abstract: Casuarina equisetifolia is an evergreen tree in the southeast coastal area of China.It grows rapidly and has strong ability to adapt to the environment.It is an excellent tree species for windbreak and sand fixation.It has made great contributions to the prevention of various natural disasters and the maintenance of natural environment stability in coastal areas of China.In order to reveal the seasonal variation of litter mass of different components of C.equisetifolia,quantify its contribution to ecosystem material cycle and energy flow,and provide scientific basis for ecological management.In this study,the monthly dynamic changes of litter mass of different components of C.equisetifolia under different sea-land gradients in this area from February 2018 to January 2019 were studied by collecting and classifying the litter of C.equisetifolia protection forest regularly every month in the fixed sample plot of Chongwu Chihu State-owned Shelter Forest Farm in Hui ‘an County,Quanzhou City,Fujian Province.The results showed that :①among the litter components of C.equisetifolia in all sea-land gradients,the amount of leaf litter was absolutely dominant,accounting for more than 70% of the total litter,and changed in a wave-like manner with the increase of sea-land gradients.The amount of branch litter changed gently with the increase of sea-land gradient.The amount of flower and fruit litter changed in a wave-like manner with the increase of sea-land gradient and showed an overall upward trend;②the monthly distribution trends of leaf,flower and fruit litters of C.equisetifolia were similar.Litters were more in the growing season of C.equisetifolia in spring and summer and had a maximum value in May,and less in winter.Leaf litters had a minimum value in February.Flower and fruit litters had a minimum value in August.Branch litters were more in typhoon-prone September and January in winter,and less in other months,with a minimum value in March.③Overall,C.equisetifolia litter at the 110 m gradient was more than at other gradients.In the growing season,C.equisetifolia litter 110 m far from the coast line was more than in other seasons,and leaf litter was the main component.