The 5, 10, 15, 20-tetrakis (3methoxy-hydroxyphenyl) porphyrin cobalt is absorbed on the surface of the glassy carbon electrode to make a CoTMHPP modified electrode.The modified electrode has high sensitivity and good electrocatalytic oxidation towards catechols for each range of their responses, and the response time is less than 10 s. The electrode possesses characteristics of high catalytic activity, fast response, good stability and a long lifetime under the optimal operations.