Abstract: In order to reveal the effects of norethisterone on aquatic organisms, 1 000 ng/L of norethisterone was used to expose marine medaka larvae（Oryzias melastigma） for 24 h to analyze the effects of norethisterone on transcription level of marine medaka larvae in the study. The results showed that norethisterone exposure significantly changed transcription patterns of 1 848 genes in marine medaka, including 728 genes upregulated and 1 120 genes downregulated. The enrichment results of GO showed that the differentially expressed genes were significantly enriched in the ways of "peptidase activity, acting on L-amino acid peptide" and "cofactor binding". KEGG enrichment results showed that differentially expressed genes were significantly enriched in iron death, DNA replication, and fatty acid metabolism pathways. Among them, in the iron death pathway, acsl4, acsl3, and gass were downregulated. All differentially expressed genes were downregulated in the DNA replication and fatty acid metabolism pathways. The results showed that norethisterone exposure could affect the transcription level of genes related to the growth and development of marine medaka larvae, and adversely affect the early development and growth of marine medaka.