For the PANDA ring-core polarization-maintaining few-mode fiber (RC-PM-FMF) with the given supported eigenmodes, the minimum effective refractive index difference min(neff) between the adjacent eigenmodes decreases with the RC size. Consequently, we propose a PANDA RC-PM-FMF assisted by a ring-sector (RS) structure, which can be used to mainly increase the neff values between the adjacent even and odd eigenmodes with the same polarization. The RS-RC-PM-FMF with an appropriate choice of the parameters can support 10 linearly polarized (LP) eigenmodes, which have min(neff) values higher than 1.910-4 for the adjacent eigenmodes over the whole C + L band. Furthermore, the fiber is characterized by the low group velocity dispersion (GVD) (?40—20 ps·nm-1·km-1) and effective mode areas (63—104 m2), while the total losses are within the range of 0.19—0.23 dB/km over the whole band.