Soils stablished by FeSO₄, FeS and Fe⁰ were chosen to study the interaction effect of pH and phosphorus on arsenic release and the mechanisms involved. The results showed that the released arsenic tended to stabilize again over time at pH 3.0, whereas increased dramatically at pH 11.0, reached 10.5, 10 and 16 times of those at pH 3.0 in 144 h, respectively. Phosphorus addition promoted arsenic release from stabilized soils, especially under acidic condition. Elovich equation could describe better arsenic release from FeSO₄ stabilized soil, while power function equation fitted better from FeS and Fe⁰ stabilized soils. Arsenic release was significantly correlated with dissolved Ca, Mg and Mn from soils at pH 3.0 and with SO₄^2- released from FeSO₄ and FeS stabilized soils at pH 11.0, which imply that arsenic release from stabilized soil is influenced mainly by dissolution of arsenic binded in Ca, Mg and Mn oxides under acidic conditions, while might relate with dissolution of sulfides in FeSO₄ and FeS stabilized soils under alkaline conditions.