With the continuous improvement of people's living standards, residents put forward higher requirements for water quality, and pay more attention to odor and taste problem. Concentrations of odor and taste compounds in 48 lakes and reservoirs of 9 cities in Pearl River Delta were detected with the method of Solid Phase MicroExtraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique. The changes of odor and taste compounds concentrations along the water treatment processes of wastewater treatment plants and water supply plants, as well as the removal effect of odor and taste compounds by enhanced coagulation-sedimentation process were studied. The results showed that:the most serious stench problem was the lakes and reservoirs of Guangzhou, Foshan, Zhaoqing, Dongguan, Huizhou and Shenzhen. The average concentrations of odor and taste compounds in the lakes and reservoirs of these 6 cities were from 70.93 to 116.61 ng/L. And the stench problem was not obvious in the lakes and reservoirs of Zhongshan, Zhuhai and Jiangmen. The average concentrations of odor and taste compounds in the lakes and reservoirs of these 3 cities were from 22.78 to 58.82 ng/L. 2-methylisoborneol (MIB), 2,3,6-trichloroanisole (TCA) and Geosmin (GSM) were the main odor and taste compounds in all lakes and reservoirs, which accounted for 80.18%-100.00% of total odor and taste compounds. The water treatment progresses of wastewater treatment plants and water supply plants could considerably remove odor and taste compounds. Coagulation-sedimentation process had the greatest contribution to the removal of odor and taste compounds. In the wastewater treatment plants, the average removal rates of MIB, TCA and GSM were 53.55%, 57.40% and 72.90%, respectively. In the water supply plants, the average removal rates of MIB, TCA and GSM were 64.14%, 69.63% and 36.86%, respectively. In the enhanced coagulation-sedimentation experiment, for the initial concentrations of odor and taste compounds of 200 ng/L, coagulation-sedimentation process could reach the greatest removal effect of them, and aluminum was not excessive as well when the coagulant (Al₂O₃) dosage was 13.75 mg/L. When the concentrations of odor and taste compounds increase, the dosage of Al₂O₃ should increase, too. When the pH value of the reaction system was between 5 and 8, coagulation-sedimentation process could reach the greatest removal effect of odor and taste compounds. The faster the stirring rate of coagulation was, the higher the removal rate of odor and taste compounds reached, and the faster the stability reached.