Heterogeneous catalyst (CaCO3-NiO) was synthesized through calcining method, and its properties were characterized by XRD, SEM, TEM and BET analyses. The effects of catalyst dosage, persulfate (PS) concentration, initial pH and inorganic anion on phenol removal were comprehensively evaluated. The results showed that phenol was completely removed after 30 min treatment under the optimum conditions (1 g/L catalyst dosage, 2 g/L PS, initial pH=11). Moreover, the degradation of phenol was based on a non-free radical mechanism, and Ni(Ⅲ) had played a dominant role.