Monoclinic　beta-Ga2O3　microbelts　were　successfully　fabricated　using　a　one-step　optical　vapor　supersaturated　precipitation　method,　which　exhibited　advantages　including　a　free-standing　substrate,　prefect　surface,　and　low　cost.　The　as-grown　microbelts　possessed　a　well-defined　geometry　and　perfect　crystallinity.　The　dimensions　of　individual　b-Ga2O3　microbelts　were　a　width　of　similar　to　50　mu　m,　length　of　similar　to　5　mm,　and　thickness　of　similar　to　3　mu　m.　The　SEM,　XRD,　HRTEM,　XPS,　and　Raman　spectra　demonstrated　the　high　single-crystalline　structure　of　b-Ga2O3　microbelts.　Twelve　frequency　modes　were　activated　in　Raman　spectra.　The　optical　band　gap　of　the　beta-Ga2O3　microbelt　was　calculated　to　be　similar　to　4.45　eV.　Upon　266　nm　excitation,　2　strong　UV　emissions　occurred　in　photoluminescence　spectra　through　the　radiative　recombination　of　self-trapped　excitons,　and　the　blue　emission　band　was　attributed　to　the　presence　of　donor-acceptor-pair　transition.　The　individual　b-Ga2O3　microbelt　was　employed　as　metal-semiconductor-metal　deep-ultraviolet　photodetector,　which　exhibits　the　photoresponse　under　254　nm.　This　work　provides　a　simple　and　economical　route　to　fabricate　high-quality　beta-Ga2O3　single-crystal　microbelts,　which　should　be　a　potential　synthetic　strategy　for　ultra-wide　bandgap　semiconductor　materials.