The invention provides a method for measuring the content of gallium in vanadium extracted waste slag and vanadium slag. The method comprises the following steps adding hydrochloric acid, nitric acid and hydrofluoric acid to a sample to dissolve the sample; adding perchloric acid and diluted hydrochloric acid to dissolve the obtained sample solution to obtain a sample solution to be measured; measuring the spectral line intensity of the sample solution to be measured by adopting a conventional inductively coupled plasma atomic emission spectroscopy method; and obtaining a corresponding gallium content value in a standard working curve of the gallium according to the spectral line intensity. The method has the advantages of convenience in operation, high accuracy of the measured gallium content and good stability, reproducibility and accuracy of a measured result, so the requirement on measuring the content of the gallium in the vanadium extracted waste slag and the vanadium slag is met.