We present a method for the spectral combination of fiber lasers with high spectral density, increasing spectral density utilization with no degradation in beam quality, and decreasing single channel narrow linewidth output power. Experiments demonstrating the utility of our method are described. The results show that we achieved 32-channel fiber laser spectral beam combining (SBC) with a beam quality of M2 = 1.68. The SBC beam quality can be constantly optimized by integrally varying the spectral interval with the feedback system. Our method offers a point of reference to broadening to additional channels and enhancing the output power of the SBC with an excellent beam quality.