Humic substances are commonly described as heterogeneous compounds containing both a large proportion of oxygen containing functional group(essentially carboxylic and phenolic)that make them and segregated aromatic and aliphatic moieties that give them surface active and hydrophobic-bonding properties.Burigonga River is located in the southestern part of the north central region of Bangladesh.Humic substances are ubiquitous in waters, being found wherever organic matter is decomposed or has been transported.For characterize and study of the complexation with metal ions,sediment samples were collected from five different places in Burigonga.Then the Humic Acids were extracted and the extracted Humic Acids were characterized with the help of IR,FTIR,SEM,EDX and CHNS analyzer.A complexation study of the Humic Acid with iron and cadmium was carried out by using SEM,EDX,UV-Visible spectrophotometer and AAS analytical instruments.From the results,it was found that iron and cadmium could make a complex at pH 6.0 which was confirmed by EDX spectrum of iron and cadmium.However,which organic groups in Humic Acid were responsible to form complexes with metals are still mysterious.