CuNiAl-LDHs were synthesized by coprecipitation method, and then the synthesized hydrotalcite-like were calcined under 600℃ to obtain the highly dispersed CuNiAl complex metal oxide as catalyst. The hydrotalcite-like compounds and complex metal oxides were characterized by FT-IR XRD and SEM. Then CuNiAl complex metal oxide was used as catalyst in ClO2 catalytic oxidation of phenol. The crystalline structure of CuNiAl-LDHs varied with the ratio of Cu, Ni and Al, and CuNiAl-LDHs with Cu/Ni/Al molar ratio of 1:1:1 had high crystallinity and single structure. CuNiAl complex metal oxide prepared by calcining CuNiAl-LDHs with Cu/Ni/Al molar ratio of 1:1:1 can catalyze ClO2 catalytic oxidation of phenol and promote the deep degradation of phenol, resulting in the increase of COD removal ratio. The COD removal ratio can reach 65% in the condition of 3g/L catalyst, pH 7.0, reaction time 60min and room temperature.