The invention relates to a method for measuring concentrations of sulfate, nitrate solutions by utilizing the terahertz time-domain spectroscopy. The method comprises the following steps: sample cells are selected, standard solution samples with different concentrations are prepared, terahertz time-domain spectra of the standard solution samples are measured, a terahertz time-domain spectra database of the standard solution samples is built, and the database comprises time-domain spectra, frequency-domain spectra, relation spectra of concentrations and absorption coefficients, relation spectra of concentrations and refractive indexes, relation spectra of concentrations and extinction coefficients of the standard solution samples. Terahertz time-domain spectra of the solutions to be measured are measured, the data is processed to obtain absorption coefficients of the solutions to be measured, and according to the terahertz time-domain spectra database of the standard solution samples, the concentrations of the solutions to be measured are analyzed and determined. The method utilizes the terahertz time-domain spectroscopy to measure solution concentrations, and is advantaged by simple operations, rapid measurement, simple data processing procedures, good repeatability, and high accuracy of results.