The oxygenation constants and thermodynamic parameter (△H°, △S°) of a series of novel Co (Ⅱ) complexes with phenol ether bridged dihydroxamic acids CoL1-CoL6 were measured,their catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The modulation of O2-binding capabilities and catalytic oxidation activities by X (X = Cl, OCH3) and Y(Y = H, CH3, Cl) groups bonded to the aromatic rings of the Co (Ⅱ) complexes were investigated.