  Cyclotron resonant scattering features (CRSFs) are the absorption features in
the X-ray spectra of strongly magnetized accretion neutron stars (NSs), which
are probably the most reliable probe to the surface magnetic fields of NSs. The
high mass X-ray binary GX 301--2 exhibits a very wide, variable and complicated
CRSF in the average spectra, which should be two absorption lines based on
NuStar and Insight-HXMT observations. With the Insight-HXMT frequent
observations, we performed the phase-resolved spectroscopy and confirmed two
cyclotron absorption lines in the phase-resolved spectra, with their centroid
energy ratio $\sim 1.6-1.7$ in the super-critical luminosity case. A major
hindrance in understanding those CRSFs is the very poorly constrained magnetic
inclination angle, which is also a fundamental property of a NS and key to
understanding the emission characteristics of a pulsar. Comparing the
phase-resolved CRSF with simulated X-ray spectra, the magnetic inclination
angle is found to be $\gtrsim 70^{\circ}$, i.e., nearly orthogonal between the
NS's spin and magnetic axies. The implications of an orthogonal rotator and
magnetic structure evolution in the accreting X-ray binary are also discussed.
