This study uses the principal component analysis (PCA) to assess the variation of surface water quality in the Bung Binh Thien area (BBT), An Giang province. The samples of surface water quality were collected at three locations in BBT (BT1-BT3), with the frequencies of three times per year in March, June and September in the period from 2009 to 2020. The parameters of temperature, pH, total suspended solids (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate (N-NO3-), ammonium (N-NH4+), orthophosphate (P-PO43-) and coliform were analysed for surface water quality assessment. The results showed that pH and temperature were within the allowable limits. The water quality at BBT was contaminated by organic matters, nutrients and coliform in which TSS and coliform were the most severe. The water quality in 2012 and 2017 was worse than the water quality in other years. PCA showed that the temperature, pH, TSS, DO, BOD, N-NO3-, P-PO43-, and coliform had significant influence on the surface water quality due to the potential pollution sources from domestic waste, livestock, aquaculture and agriculture.