This study was carried out to identify the impact of some environmental variables including water surface temperature, air pressure, and wind current speed on the catch rate of grouper fish (Epinephelus coioides) using long line method in the north west water of the Persian Gulf (coastal province of Khuzestan). Sampling was carried out in three seasons of spring, summer and autumn in 1391 and two seasons of summer and autumn in 1392. Data analysis revealed high correlation among current speed, air pressure and catch rate. The study showed that the amount of catch in the summer increased significantly with a rise in surface temperature, air pressure and a decrease in current speed. Therefore, summer is better than other seasons to catch this species