Meiofauna samples from intertidal sediments of Qingdao No.2 Bathing Beach,China,were collected for field study,and subjected to organic enrichment in a laboratory microcosm experiment for 21 d.There were three different treatments including non-organic addition as the control,low-organic enrichment (2 g DW green algae per 150 mL) and high-organic enrichment (10 g DW green algae per 150 mL).After 21 d,the meiofauna richness decreased in both organic enrichment treatments.Among the three treatments,total meiofauna abundance was significantly different,and the control groups had higher abundance than the other two treatment groups.However,the responses of the meiofauna abundance in the two organic enrichment treatments were non-significantly different.The relationship of meiofaunal abundance and nematode/copepod ratios to organic matter and oxygen level in the microcosm experiments were discussed.