Investigation of whole genome gene expression level changes in zebrafish liver under naphthalene treated（high-concentration group and low-concentration group）, compared to the solvent control group revealed that 76 genes and 88 genes were differentially expressed respectively in the fish caged at the low-concentration and high-concentration. KEGG pathway and GO analysis of the differentially expressed genes, showed significant enrichment in several meaningful categories. Overall design: Healthy 5-month-old adult zebrafish (AB strain) maintenance and chemical exposure to 84μg/L and 840μg/L naphthalene and 0.005% Dimethyl sulfoxide as the solvent control were performed according to published research protocols. Prior to exposure, the fish were acclimatized in 50L aerated fresh water in glass tanks for 2 weeks, under controlled environmental conditions with the water temperature maintained at 26±0.5℃ for 16-h light and 8-h dark photoperiod. After 21 d of treatment, adult zebrafish livers were removed by dissection, and immediately transferred to RNA-later Stabilization Reagent(Qiagen,76106) , prior to storage at 4℃ for histopathological and microarray analysis. NimbleGen Gene Expression 12X135K zebrafish microarrays and One-Color DNA labeling Kit (NimbleGen, WI) were used for genome-wide expression analysis of naphthalene-treated zebrafish.