The spatial distribution and temporal variation of aerosol optical depth (AOD) and the characteristics of chlorophyll a concentration (Chl-a) in the Arabian Sea, were inter-annually and seasonally analyzed by utilizing the MODIS/Aqua AOD and chlorophyll products during 2003 to 2017, and the relationship between the aerosol and chlorophyll a concentration was discussed for the sea area. The results showed that the spatial distributions of AOD and Chl-a changed more significantly with the seasons in the Arabian Sea, and generally showed a gradual decrease from offshore to the open seas. The value and spatial distribution of the AOD and Chl-a were obviously affected by the dust in the land-sourced desert. The AOD was higher in summer than spring, and in winter was higher than that in autumn. During the past 15 years there appeared an increasing trend of the AOD, especially in its east coastal area, but no significant change occurred in the north coast. The specific performance of Chl-a was higher in autumn and winter, lower in spring and summer, and its variability was high. From the correlation coefficient analysis between AOD and Chl-a in spring and winter, the correlation between AOD and Chl-a was significantly correlated in the northwestern Arabian Sea, and it showed a trend of decreasing from north to south and from the coast to the outer sea.