In order to realize the output of high power semiconductor laser with uniform brightness, symmetrical shape and high symmetrical beam quality, a high power fiber-coupled diode laser system based on mini-bar was proposed, and Zemax was used to simulate a 500 W-output fiber-coupled diode laser system with a fiber of 200 μm core diameter and 0.22 numerical aperture. In the system, mirror-stripe mirror system was put forward to compress the beam size in the fast axis of diode array in terrace structure, and polarization multiplexing was used to double the output power without changing the beam parameter product. Then, a beam expander system was taken to reduce the residual angle in slow axis, and an aspherical lens was used to coupled the shaping beam into the fiber. Based on the existing condition, 4 diode laser arrays (each contains 5 mini-bar) in terrace structure were used to validate the design. The output power of the fiber-coupled diode laser system can achieve 506 W, and the brightness is 10.3 MW/(cm2·sr), while the E-O efficiency is 43.0% at operation current of 37 A. Design and experiment all show the fiber-coupled diode laser system can work steadily with output power over 500 W. This module can be used in material processing and many other areas.