Dissolved organic matter (DOM) can mediate electron transfer and change chemical speciation of heavy metals. In this study, the electron transfer capability (ETC) of compost-derived DOM was investigated through electrochemical approaches, and the factors influencing the ETC were studied using spectral and elemental analysis. The results showed that the electron accepting capacity (EAC) and electron donating capacity (EDC) of compost-derived DOM were 3.29-40.14 mu mol(e-) (g C)(-1) and 57.1- 346.07 mu mol(e-) (g C)(-1), respectively. Composting treatment increased the fulvic- and humic-like substance content, oxy-genated aliphatic carbon content, lignin-derived aromatic carbon content, molecule weight, and N and S content of DOM, but decreased the aliphatic carbon content and the C and H content. This conversion increased the EDC and EAC of the DOM during composting. (C) 2014 Elsevier B.V. All rights reserved.