Reactive extractions of o-, m-, and p-aminophenol (OAP, MAP, and PAP) using trialkylphosphine oxide/kerosene (TRPO/kerosene) have been studied. The equilibrium aqueous pH (pH(eq)) and the concentrations of TRPO in organic phases were found to be of important effects on the distribution coefficient (D) of OAP, MAP, and PAP between TRPO/kerosene and water. Infrared spectra results suggested pH(eq) had no influence on the complexes' structures, and TRPO mainly reacted with neutral aminophenol through forming a hydrogen bond between its P=O and aminophenol OH. An expression of D was proposed, and the apparent reactive extraction equilibrium constants (K) were calculated by fitting the experimental data. The dissociation constant of the OH group of aminophenol (namely, pK(a2)) played a vital role that affected K, while the hydrophobic parameter (log P) of aminophenol had little effect. K was statistically calculated to be in accordance with the equation of log K + pK(a2) = 10.94 under all experimental test conditions. D values calculated from the model were in good agreement with experimental ones.