The contents of bioavailable phosphorus (BAP) in sediments from the centre of Lake Hongfeng,Guizhou Province and its main estuaries were analyzed by chemical extraction, and the relationships between spatial distribution of the BAP and size compo-sition of the total phosphorus (TP)were also discussed. Results showed that rank orders of the BAP forms was;Algal Available Phosphorus (AAP)>NaHC0₃ extractable phosphorus(Olsen-P )>Water Soluble Phosphorus(WSP )>Readily Desorbable Phosphorus(RDP). The variation trend of the BAP with decreasing drastically downward in the sediment core was more remarkable than that of TP. There were multiply correlation among various BAP forms and TP, except for RDP and AAP. Olsen-P was the best index to evaluate phosphorus bioavailability in sediments from Lake Hongfeng. Clay and silt were the main sediment fractions, while the sediment particle size in the centre part were smaller than those in estuaries. Olsen-P and AAP in the top Scm sediments of the core were positively correlated to the proportion of fine fraction (< 0. 002mm ),whereas RDP and WSP were negatively correlated to, suggesting that the fine fraction has an important contribution for promoting eutrophication in deep lakes.