Laser　irradiation　of　semiconductors　has　attracted　considerable　attention　due　to　its　important　background　in　all　kinds　of　applications.　Unfortunately,　it　has　rarely　been　applied　to　optimize　the　morphology　of　the　active　layer　in　organic　photovoltaics　(OPV).　This　work　provided　previously　unavailable　information　about　the　effect　of　laser　annealing　(LA)　on　the　morphology　and　function　of　OPV　and　its　comparison　to　thermal　annealing　(TA).　The　results　showed　that,　compared　with　TA,　the　active　layer　treated　with　LA　tended　to　form　smaller　donor　crystals　and　a　face-on　structure,　which　facilitated　hole　transport.　Moreover,　small　angle　neutron　scattering　(SANS)　experiments　showed　that,　compared　to　TA,　acceptor　phase　separation　was　suppressed　by　LA　and　became　weaker　with　an　increase　of　laser　intensity.　Furthermore,　the　maximum　interfacial　area　between　the　acceptor　phase　and　its　surrounding　matrix　was　achieved　with　proper　laser　intensity,　which　is　found　to　be　crucial　for　electron　transport,　bimolecular　recombination,　and　subsequent　device　performance.　Finally,　the　generality　of　femtosecond　LA　on　the　optimization　device　performance　of　OPV　including　fullerene　and　nonfullerene　systems　was　also　investigated.　The　findings　in　this　work　shed　light　on　the　application　of　LA　for　the　further　improvement　of　OPV　device　performance.　©　2019　American　Chemical　Society.