Surface water plays an important role in human life and ecosystems. Monitoring surface water quality to identify tendency and causes of change, and to propose management solutions is very necessary. This study evaluates surface water quality in the canals of An Giang province in the periods from 2009 to 2016 using water quality monitoring data provided by the Department of Natural Resources and Environment of An Giang province. The results show that the surface water quality of the canals is contaminated by organic matter and microorganisms and is unsuitable for the water supply as well as the conservation of aquatic life. The water quality parameters such as dissolved oxygen (DO), biological oxygen demand (BOD), total suspended solids (TSS), orthophosphate (P-PO43-) and coliform levels in the wet season are found to be higher than those in the dry season. The problem of organic pollution and microorganisms has been known for over a long period of time, but no solution has been found out. Agriculture is the main contributor to the pollution of surface water in interior canals along with daily and industrial activities. This impacts the surface water of the Hau river due to its water exchange with the connected canals. Thus, good agricultural practices should be implemented to reduce the pollution of surface water resources in Mekong Delta.