The invention relates to a method for measuring content of acrolein in a liquid-phase mixture. The liquid-phase mixture mainly contains acrolein, acrylic acid and acetic acid. The method comprises following measuring steps: firstly, molar concentration of total acid in a to-be-measured liquid is measured with an acid-base titration method; acrylic acid and acetic acid are measured with gas chromatography, and concentration of acrylic acid is measured; then a bromine salt solution and a sodium thiosulfate solution are utilized to titrate acrolein and acrylic acid, molar concentration of an acrolein and acrylic acid mixture is obtained, and finally, molar concentration of acrolein is obtained. The measuring method is low in cost and simple and convenient to operate, has low requirement for atesting environment, and does not need large analytical equipment, and a measurement result is accurate.