In this paper, the concept of “combined array mode” for laser diode bar is proposed, and the far-field profile of “combined array mode” is calculated. The far-field of each combined array mode exhibits a two-lobe profile with different angular position. On the basis of the characteristic of far-field profile of combined array mode, an off-axis external cavity feedback laser diode bar is designed. By employing the setup, the far-field profile of laser diode bar is narrowed by 4.3 times compared with the free-running laser diode bar. The output power of external cavity feedback laser diode bar is about 1.82 W at the drive current of 16 A, or 79% of the radiated power of the free-running state. The theory of combined array mode cannot only be applied to design the external cavity feedback laser diode bar but also can be designed the external cavity feedback laser diode stack.