In this paper, A polarization full-feedback open-loop spectral beam combining (PFF-SBC) strategy based on parity-time symmetric double-ridge stripe semiconductor laser diodes (PTLD) is proposed and demonstrated. The beam quality of the PTLD is optimized and the combining efficiency is improved by using the methods of polarization separation and full feedback. The maximum output power is up to 2.71 W, which leads to a spectral beam combining efficiency of 83.4% and a grating diffraction efficiency of 95.51% under continuous current operation at a current of 2.3 A. Additionally, the brightness of the SBC module is 116.2 MW∙cm-2sr-1 at a current of 1.6 A, which is 3.5 times that of a single PTLD. The PFF-SBC strategy provides a new approach for increasing the beam brightness of PTLD.