  We report optical observations of the millisecond pulsar binary system PSR
J1622-0315 with the Lulin 1m telescope in Taiwan and the Lijiang 2.4m telescope
in China between 2019 and 2021. The companion of the pulsar, which is of V~19
mag, showed ellipsoidal-distorted orbital variations in its light curves. The
best-fit model to the light curves, with the binary code PHOEBE, gives a
companion mass of 0.122+/-0.006 M_sun. This places PSR J1622-0315 in the
spider-system subclass. We compared the properties of PSR J1622-0315 with other
spider pulsar binaries for the scalings between the spin-down luminosity
derived for the pulsar, irradiation luminosity of the companion, and X-ray
luminosity of the binary. We find that pulsar irradiation in PSR J1622-0315 is
insignificant and the irradiation luminosity of the transitional millisecond
pulsars PSR J1023+0038 and PSR J1227-4853 are the highest among the redback
systems.
