Evaluation and monitoring of the effects of pollutants in a biologic environment requires the identification of a suitable biomarker. In this study, the expression of CYP1 gene as a biomarker of petroleum pollutants in Scatophagus argus at three stations (Peleh Abad, Jebra and Harbor), and control samples Reviewed. Comparison of expression of CYP1A gene expression in the liver in all regions was not significantly different from the control. There was no significant difference between the expression regions in the samples of Peh-Abad and Jebra's ports, but both regions showed a higher expression than the ports of the harbor. The expression of CYP1A gene in gilts of Zorooc fish showed a significant increase compared to control. There is also a significant difference in the expression of gene expression in the three sampling sites. The highest glycemic expression of CYP1A gene was observed in Kholestanian samples. And the lowest amount of CYP1A gene expression in gills was observed in Zorooc fish gills in Harbor area samples. Regarding the association between the expression of CYP1A2 gene in gill and liver tissue and the extent of contamination of regions, the expression of the CYP1A gene can be used as an appropriate biomarker for PAH contaminants.