Disclosed is a method for measuring dislocation density of steel through the electron back-scattered diffraction (EBSD). The method includes preparing standard samples and a plurality of to-be-testedsamples, sequentially placing the samples in an scanning electron microscope with the EBSD, scanning the samples and recording scanning data, processing the scanning data, determining interfacial density Pi(standard) of small-angle interface of the standard sample and interfacial density Pi of small-angle interface of the to-be-tested samples, measuring dislocation density d (standard) of the standard sample, calculating the constant k by the formula d(standard)=k*Pi(standard), and then calculating the dislocation density of the to-be-tested samples by the formula d=k*Pi. Compared with the other conventional method for measuring dislocation density, the method is much convenient and accurate, and can measure and compare the dislocation density of different steel products visually.