The　sluggish　kinetics　and　high-power　consumption　of　the　oxygen　evolution　reaction　(OER)　are　recognized　as　major　barriers　in　electrocatalysis.　Therefore,　exploring　cheap　and　highly-efficient　OER　electrocatalysts　is　highly　desired　for　improving　energy　storage　and　conversion.　Related　Fe-based　materials　have　been　widely　applied　in　OER　electrocatalyst　field　due　to　their　excellent　OER　activity.　Herein,　we　adopt　the　vacuum　annealing　and　electrochemical　dealloying　methods　to　produce　a　self-supporting　np-Fe40Co40B20-800-5min　catalyst　enriched　with　nanocrystalline.　The　self-supporting　np-Fe40Co40B20-800-5min　catalyst　exhibits　superior　OER　performance　with　an　overpotential　of　315　mV　at　a　current　density　of　10　mA　cm-2　and　a　small　Tafel　slope　of　26　mV　dec-1.　The　overpotential　of　the　np-Fe40Co40B20-800-5min　catalyst　is　boosted　by　more　than　20　percent　over　that　obtained　npFe40Co40B20　catalyst.　The　active　intermediates　were　explored　by　in　situ　Raman　under　catalytic　conditions.　The　indepth　mechanism　research　suggests　that　the　nanocrystalline　may　serve　as　an　advantageous　electrocatalytic　species　in　amorphous　np-Fe40Co40B20-x-ymin　catalyst.　This　study　offers　a　novel　approach　to　promoting　catalytic　properties　in　an　amorphous　np-Fe40Co40B20-800-5min　catalyst　based　on　enriched　nanocrystalline.