CaTiO3　nanoparticles　(NPs)　with　diverse　morphologies　have　been　successfully　synthesized　by　the　precursor　morphology-controlled　formation　based　on　a　facile　hydrothermal　approach.　The　fabricated　CaTiO3　NPs　were　characterized　by　X-ray　diffraction,　field　emission　scanning　electron　microscope,　high-resolution　transmission　electron　microscopy,　electron　spin　resonance,　X-ray　photoelectron　spectra,　and　electrochemistry　technology.　It　is　found　that　the　morphologies　of　as-synthesized　CaTiO3　NPs　are　strongly　dependent　on　the　aggregate　status　of　the　titania　hydrogel　precursors.　Especially,　the　as-prepared　CaTiO3　NPs　was,　for　the　first　time,　used　as　the　highly　efficient　photocatalysts　to　remove　arsenite　from　aqueous　solution.　Due　to　their　unique　morphologies,　the　fern-like　CaTiO3　NPs　exhibit　a　high　photocatalytic　activity　toward　the　oxidation　of　As(III)　(up　to　98.4%)　under　irradiation.　The　photogenerated　holes　(h+)　are　recognized　as　the　primary　active　species　responsible　for　As(III)　oxidation.　Meanwhile,　a　possible　mechanism　for　the　photo-oxidation　of　As(III)　over　CaTiO3　has　also　been　proposed.　©　2014　Elsevier　B.V.