Butyltins in surface water, sediments and biota samples from Taihu Lake were determined. The results show that butyltins content in most of the surface water samples is under the limit of the detection; five out of ten sediment samples are measured detectable butyltins. Monobutyltin (MBT) was the main species with the concentrations ranging from below the detection limits to 0.95 ng/g; while all biota samples were detected relatively higher butyltin concentrations with a range of 27.05 - 181.23 ng/g due to the obvious bioaccumulation. Tributyltin (TBT) was the main composition that occupied almost 70% of the total butyltins. The antifouling paints applied on the aquatic cultural box and boats was the possible main source of butyltin compounds in Taihu Lake.