The invention relates to an acid-free electrolytic cleaning fluid and application thereof in a bethanizing production line. The acid-free electrolytic cleaning fluid consists of the following components in percentage by weight: 15% of silicate, 1% of alkali carbonate, 0.2% of glycine betaine and the balance of deionized water. By means of the effect of silicate and carbonate and assistance of amphiprotic activation of dodecyl dimethyl betaine, the interface tension of metal and an electrolytic cleaning agent is reduced under the polarization effect of a direct current, and liquor permeates below dirt and corrosion on the surface of a workpiece. Oxidation or reduction effect occurs to the interface, and a lot of bubbles are generated. When the bubbles are gathered to form an air flow which escapes from a gap between the dirt and the metal, the bubbles have the agitating and stirring and peeling effects, so that dirt and corrosion fall from the surface of the workpiece.