The invention discloses a simple titanium alloy corrosion machining tank liquor control method, which comprises the following steps: (1) preparing components of initial corrosion machining solution; and (2) corroding a titanium alloy with the initial corrosion machining solution, periodically analyzing the titanium ion content of the solution, and supplying solution components for each 10g/L increase in the titanium ion content, wherein the solution components include hydrofluoric acid in an amount which is 1/2 of the initial amount, hydrogen nitrate in an amount which is 1/6 of the initial amount and additive in an amount which is 1/2 of the initial amount. The method has the advantages of ensuring stable corrosion machining production, improving machining speed, relieving surface roughness, meeting requirements of corrosion machining production and prolong the service life of the corrosion machining solution on the premise of no influence on production efficiency and surface quality, wherein in the whole machining process, the corrosion machining speed is 0.008 to 0.016 mm/min on a single side, the surface roughness is less than or equal to 0.8mu m, and the chemical milling depth different is +/-0.08mm.