In　the　present　study,　the　magnetic　domains　and　their　evolution　during　magnetization　process　have　been　investigated　for　sintered　Nd-Fe-B　permanent　magnets　with　Kerr　microscopy.　Observation　of　the　magnetic　domain　evolution　process　during　magnetization　process　shows　that　some　domain　walls　were　pinned　at　the　grain　boundary　area　under　magnetic　field　up　to　5　kOe.　It　is　suggested　that　magnetic　interaction　between　individual　Nd2Fe14B　grains　contacting　to　each　other　leads　to　appearance　of　small　closed　domains　near　the　grain　boundary　area,　which　are　responsible　for　the　pinning　effect.