The Siak River is recorded as the deepest rivers in Indonesia and used as main transportation route since long time ago for bid ship. Due to high human activities, most of the natural resources are disturbed; however there is limited studies related to impact of disturbance on natural resources. This study aimed to record the natural resources of the Siak River both vegetation and fisheries as well as to assess the environmental stress due to human activities around the areas. About 26 species of dominant vegetation was recorded which exotic and invasive plant species had invaded the catchment areas of the Siak River. Fish population and fishermen income were recorded decreasing due to increasing the environmental disturbances. Due to land conversion, sedimentations were occurred. Then environmental pressures on the Siak River were intense by the rapid development of industries and the pollutants are causing risk for humans, biodiversity and environment. Therefore, a good catchment area management need to be implemented to restore the natural resources of the Siak River ecosystem.