The invention relates to an electrochemical reducing method of carbon dioxide in ionic liquid and an electrochemical reducing device. The method comprises following steps: injecting ionic liquid in a cathode chamber in the electrochemical reducing device, inputting the carbon dioxide, inputting hydrogen on the inner side of an anode bipolar plate, oxidizing the hydrogen on an anode, generating hydrogen ions, enabling H+ to traverse through proton exchange membrane to reach a cathode, transmitting electrons to the cathode through an external circuit, enabling the carbon dioxide and the H+ to generate electrochemical reduction reaction on the cathode, generating organic compound such as carbinol and the like, and obtaining the carbinol, water and other secondary reaction products through distilling the organic compound which is generated. The ionic liquid of the invention has very high electrical conductivity and ion mobility, the ionic liquid is suitable to be used as a media system of electrochemical reaction, simultaneously, the ionic liquid has the advantages of low volatility and small toxicity, competitive reaction of the H+ is inhibited, since the solubility of the carbon dioxide in the ionic liquid is very high, the efficiency of the electrochemical reduction reaction of the carbon dioxide is also comparatively high, and the electrochemical method of the invention utilizes CO2 to generate the organic compounds such as the carbinol and the like (by products are aminic acid, formaldehyde and the like), which realizes the resource utilization of the CO2.