Distribution of meta-aminophenol (MAP) between water and trialkylphosphine oxide (TRPO), dissolved in different diluents (1-octanol and kerosene), as well as a comparison with the extraction equilibrium of pure diluent alone has been studied. The influence of the pH value of aqueous solutions, the TRPO concentration and diluents on the distribution ratio D has been discussed. ne results indicate that the pH value and the TRPO concentration are the key factors that affect D. The non-polar diluent (kerosene) is favorable for extracting MAP when TRPO is used as extractant. MAP can be extracted with both acidic and neutral extractants (Di(2-ethylhexyl)phosphoric and TRPO) efficiently in kerosene while the basic one (Alamine 336) in 1-octanol, and their efficient pH region is 2.5-3.5, 4.5-6.5, and 6.5-7.8, respectively. The extraction ability shows the order of TRPO/kerosene >= Di(2-ethylhexyl)phosphoric/kerosene > Alamine 336/1-octanol. The best selection is TRPO/kerosene with initial pH at 5.5-9.5.