We examined the microstructural parameter ?? in order to investigate the influence of its components on the intrinsic coercivity of an isotropic Nd-Fe-B sintered magnet. By applying boundary conditions for the assessment of grain (mis)alignment ???? and exchange coupling ??exc and combining with magnetic measurements and structural characterization results obtained by magnetic small angle neutron scattering, the parameter ??K???associated with the reduction of the magnetocrystalline field???plays a major role on the reduction of coercivity of the case study. Approaches in determining?????K???are also discussed.