Fiber-coupled diode laser output system is often used for pumping source of fiber laser, and it is one of the key elements of fiber laser. Aimed at multi-mode fiber of 105 μm core diameter and 0.15 numerical aperture, a high brightness fiber-coupled diode laser system based on dual-emitters is designed by using Zemax software. In the system, the high precision collimation technique, spatial multiplexing used steps and mirrors, polarization multiplexing and slow axis beam expander technique are taken to achieve beam shaping. Finally, an aspherical lens is used to focus and couple the beam into the target fiber of 105 μm core diameter and 0.15 numerical aperture. Combined with the design, the equivalent confirmatory experiment is carried out based on the existing experimental condition. The simulation and experiment all show that, the system can couple 16 dual-emitters into a fiber of 105 μm core diameter and 0.15 numerical aperture, the stable output power can reach 154 W, the brightness is up to 25 MW/( cm2·sr), and the electro-optics efficiency is 42% at injection current 15 A. This system can be widely used in pumping fiber laser, manufacture processing and other fields after been engineered.