A sensitive and selective electrochemical sensor based on poly-(nicotinic acid) (PNA) film and Cd-doped ZnWO4 (Cd-ZnWO4) nanoneedles organic-inorganic nanocomposite modified carbon paste electrodes (PNA(ii)/Cd (0.02)-ZnWO4/CPE) is successfully constructed and applied to study the catalytic oxidation of hydroquinone (HQ) and catechol (CC). X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical techniques are used to characterize the composition, morphology and electrochemical properties of the modified electrode. The sensor exhibits strong electrocatalytical activity towards the oxidation of HQ and CC for the higher specific surface area of Cd-ZnWO4 nanoneedles, fluent electron transfer capacity and the synergistic effect of inorganic Cd-ZnWO4 and organic PNA. Wide linear ranges are obtained as 1-56 mu M for HQ and 2-35 mu M for CC, with the detection limits of 0.17 mu M and 0.03 mu M, in the differential pulse voltammetry (DPV) determination of HQ and CC, respectively. Satisfactory repeatability, stability and anti-interference performance are also achieved on PNA (ii)/Cd(0.02)-ZnWO4/CPE. Meanwhile, the proposed sensor realizes the detection of CC and HQ spiked in local tap water samples successfully.