Abstract: Study of the selenium enrichment ability for an mangrove plant Pluchea indica endophytic fungus by means of single factor and orthogonal experiments, in order to obtain organic selenium.The influence factors such as selenium solution added amount, salt concentration, carbon source concentration, culture time and carbon source were optimized with the total selenium accumulation as the index in the experiment. The results showed that when the enriched culture medium was contained salt concentration 5 g/L, selenium solution added volume 30 mL, carbon source(glucose)concentration 15 g/L, culture time 24 h, the total selenium accumulation was 1941.7 g/L, the mycelium Se content of up to 181.6 μg/g and the lower organic selenium transformation rate was 16.2%. It is expected to provide theoretical basis for further researching selenium rich microbial resources in coastal mangrove plants.