Abstract: OBJECTIVE To establish a method to quickly determine the content of calcium disodium edetate injection. METHODS Resonance light scattering spectroscopy was used to determine the intensity difference of the resonance light scattering spectra before and after the reaction of calcium disodium edetate and sodium oxalate under the alkaline condition of 0.01 mol·L^-1NaOH. RESULTS When the excitation and emission bandwidth was 5.0 nm and the scanning speed was 2 000 nm·min^-1, the calcium ions dissociated by calcium disodium edetate and oxalate formed calcium oxalate molecules, which weaken the intensity of the resonance light scattering spectrum of the system. When the excitation and emission wavelengths were both at 273 nm, the difference in the intensity of the resonance light scattering spectrum of the system was the largest, and the relationship was linear in the range of 0.30-1.20 mg·L^-1, and the correlation coefficient R=0.999 2. The detection limit of this method was 0.005 8 mg·L^-1 and the limit of quantification was 0.019 3 mg·L^-1. CONCLUSION This method is highly sensitive, specific, time-saving and simple. It can be used for the content analysis of calcium disodium edetate injection. The measured value is basically consistent with the volumetric analysis method.