In order to suppress angular glint in monopulse radar system, a novel method for angular estimation basing on spectrum entropy maximization is presented in this paper. Spectrum widen of difference beam echoes due to the pattern modulation is investigated. Basing on the relations between the spectrum widen, target angular motion center and waveform entropy, a novel method by searching maximum waveform entropy for angular estimation is presented to suppress angular glint. Compared with high-range-resolution angular estimation method available, the novel method performs more conspicuously in angular glint suppression. Simulations show the effectiveness of the new method