Large eddy simulation is conducted to analyze the flow structures around a propeller of a multirotor unmanned aerial vehicle (UAV). The propeller consists of two blades, and the angle of attack of blades varies along the spanwise (radial) direction. An immersed boundary method is used to satisfy the no-slip condition on the propeller surface in a non-inertial reference frame (Kim and Choi,2006). A global dynamic subgrid-scale model (Lee et al.,2010) is used for the subgrid-scale stress tensor. The Reynolds number based on the tip velocity and chord length at the 75% span is about 73000. The lift coefficient from the present numerical simulation is in good agreements with that from experiments. The flow around the propeller is nearly attached on the surfaces, and wingtip vortices are generated near the tip of the propeller during rotation. To predict the performance of the propeller, the sectional lift coefficient is obtained along the spanwise direction and compared with the models derived using the thin airfoil theory and actuator disk model, showing good agreements.