In the present study, flow characteristics of turbulent pulsating flow in a square-sectional 180$^{circ}$curved duct were experimentally investigated. The experimental study for air flows in a curved duct are carried out to measure axial velocity profiles, wall shear stress distributions and entrance length in a square-sectional 180$^{circ}$curved duct by using the Laser Doppler Velocimeter(LDV) system and the data acquisition. Velocity profiles are obtained using the Rotating Machinery Resolver(RMR)and PHASE software in case of turbulent pulsating flow. Finally, it was plotted by the ORIGIN software. The experiment was conducted in seven sections from the inlet (ø = 0$^{circ}$) to the outlet (ø=l80$^{circ}$) at 3 0$^{circ}$intervals of the duct.