In order to understand the spatial and temporal distribution patterns and germination of seed rain of Casuarina equisetifolia, the spatial-temporal distribution characteristics and germination dynamics of seed rain were studied in coastal protection forest of C. equisetifolia in Haikou, Hainan Province. The results showed that the seed rain of C. equisetifolia began in mid-July and finished in mid-April of next year, which was lasted for 9 months, with average density of seed rain for 1 764.63 grain m^-2a^-1. The peak of seed rain was in early-to mid-December, accounting for 43.38% of the total seed rain. Seed rain was aggregated distribution, and the seed rain density was positively correlated with the number of nearby cones. The germination rate of seed rain was low only with 11.31%, but the germinable seed rain density was still high with 199.58 grain m^-2a^-1, due to the high seed rain density. Therefore, the quantity and quality of C. equisetifolia seed rain were not the main factors in restricting its natural regeneration, but the aggregated distribution pattern made the diffusion ability of C. equisetifolia seeds very limited in the forest.