The invention discloses compound ionic liquid braunification liquid for printed-circuit boards. The braunification liquid comprises the following raw materials according to the mass concentrations in the braunification liquid: 70-120 g/L acidic functionalized ionic liquid, 5-20 g/L hydrogen peroxide, 5-15 g/L an ionic liquid corrosion inhibitor and 0.5-5 g/L ionic liquid binding force accelerant, wherein the acidic functionalized ionic liquid is imidazole functionalized ionic liquid with substituted sulfonic group with the side chain length of C2-C8 or substituted carboxylic group, pyridine functionalized ionic liquid or quaternary ammonium salt functionalized ionic liquid; the compound ionic liquid braunification liquid adopts sulfate radical, trifluoro sulfoacid radical and dihydrogen phosphate as negative ions; the density of the obtained braunification liquid is within 1-1.45 g/mL, the pH value is smaller than 4, and the copper loading capacity can reach up to 60 g/L; the braunification liquid has stable binding force with prepregs and good heat resistance, and has remarkable environment-friendly superiority due to the environment-friendly property and nonvolatility of the ionic liquid.