The decomposition process of peat bog soil (peat soil) is a key process to control the carbon emission of peat soil, and dissolved organic matter (DOM) is the main output of the peat decomposition process. DOM is rich in functional groups with redox properties, of which phenol groups have antioxidant properties and are important parts of the DOM redox activity, which are of great significance for driving the redox process under aerobic and anoxic conditions. Moreover, phenolic groups can inhibit the oxidative degradation of peat and therefore play an important role during the decomposition of peat soil. At present, there are few related studies on the influence mechanism of DOM redox capacity during peat decomposition. This study used innovatively mediated electrochemical analysis and excitation-emission fluorescence matrix (EEM) to quantitatively and qualitatively evaluate the degree of DOM redox changes, and then explored (1) DOM redox capacity in the surface water, groundwater, and pore water samples taken from two peat samples (OS/LB); (2) variations of DOM redox capacity and its relationship with important indicators of peat decomposition (such as C/N and δ¹³C_DOC) in the peat pore water profile from peat sample OS. The results showed that we chose the electron transfer capacities (ETC) as the index to characterize the redox ability of DOM, and the ETC values of DOM from different origins were mainly between 2-4 mmole^-/gC. Significant correlation of redox properties of DOM with spectroscopic quality parameters for quinone and phenol moieties supported that these groups had great influence on the redox activity of DOM in peat soil. The specific performance was as follows: in the sampling area OS, 5-50 cm depth and 0-210 cm depth peat pore water profiles, phenol groups were always an important part of the DOM redox activities at any depth, while quinone groups only played an important role near the surface of 20 cm depth, where was no flooding and aerobic. The changes of DOM redox capacity along peat bog pore water profiles were mostly affected by the change of phenolic content of peat itself caused by the different degrees of peat decomposition during peat decomposition, especially in greater depth without the influence of water table fluctuations. This study explores the change characteristics and influence mechanism of the DOM redox capacity during peat decomposition, and provides theoretical support for clarifying organic matter and biogeochemical processes in peat swamp wetlands.