In this paper, optical limiting effect is studied based on the stimulated Brillouin scattering (SBS) in a single-mode fiber. Nonlinear propagation has been numerically analyzed and computationally treated in the transient SBS progress. Optical limiting, stabilization and output pulse shape have been demonstrated when high-power laser pulses enter a fiber when SBS occurs. Experimental investigation of optical limiting performances predicted by theory has been conducted using a 100 μm-diameter fiber. The input optical signals are Nd∶YAG nanosecond laser pulses which widths are 16 ns, superior constant output energy was gained when the intensity of input pulse change in experimental regime. When the input energy varied between 100～400 μJ, the fiber system gives relative stable output energy between 65～85 μJ. So the experiment results showed the optical limiting performance based on SBS in a fiber.