This　study　focused　on　the　in-hover　aerodynamics　of　a　small　rotor　with　a　thin　circular-arc　airfoil　and　a　convex　structure　at　a　low　Reynolds　number.　The　method　combined　computational　fluid　dynamics　(CFD)　with　the　blade　element　momentum　theory　(BEMT).　The　former　was　used　for　studying　the　two-dimensional　parametric　aerodynamics　of　the　airfoil　at　a　low　Reynolds　number　and　the　latter　was　used　for　the　prediction　of　the　rotor＇s　hover　performance.　A　novel　thin　circular-arc　airfoil　with　a　convex　structure　with　a　high　aerodynamic　performance,　high　structural　strength,　light　weight　and　easy　manufacturing　process　is　presented　in　this　paper.　A　convex　curve　on　the　upper　surface　was　adopted　to　increase　the　thickness　of　the　airfoil　at　partial　chord,　and　a　stiffener　in　the　airfoil　was　installed　to　improve　the　structural　strength　of　rotor　span-wise.　The　aerodynamic　performance　of　the　airfoil　was　numerically　simulated　by　the　two-dimensional　steady　and　incompressible　Navier-Stokes　equations.　The　in-hover　performance　of　the　rotor　for　small-scale　vehicles　was　predicted　by　an　improved　version　of　the　blade　element　momentum　theory　(BEMT).　Finally,　a　carbon-fiber　rotor　with　the　presented　airfoil　was　manufactured　that　had　a　diameter　of　40　cm　and　a　pitch　of　6.2　inches.　The　analysis　results　were　verified　by　experiments.　It　was　shown　that　the　maximum　calculation　errors　were　below　6%.　The　improved　BEMT　can　be　used　in　the　analysis　of　in-hover　micro-rotor　aerodynamics　at　low　Reynolds　numbers.