In the case of the direct measurement of 226Ra using a HPGe gamma-ray spectrometer, the interference between gammarayswith 186.21 keV of 226Ra and 185.7 keV of 235U should be corrected to calculate the net peak area in the energy spectrum. In general, it is very difficult to conduct peaks stripping with difference of about 0.5 keV, although a HPGe with thesuperior resolution is applied and the maximum channels is applied to the spectrometer. In this study, several interferencecorrection techniques in the direct measurement were surveyed to evaluate the feasibility for the measurement of 226Ra usingthe gamma-ray spectrometery. Applying the interference corrections to the analysis of raw materials and by-products,the method validation for the direct measurement of 226Ra was conducted by evaluating the measurement uncertainty,linearity, and range. As a result, the optimum method of the interference correction was selected by comparing with theindirect measurement of which progenies of 226Ra, such as 214Pb and 214Bi, were analyzed in the secular equilibrium state.