  I show the formulation of de Sitter Special Relativity (dS-SR) based on
Dirac-Lu-Zou-Guo's discussions. dS-SR quantum mechanics is formulated, and the
dS-SR Dirac equation for hydrogen is suggested. The equation in the earth-QSO
framework reference is solved by means of the adiabatic approach. It's found
that the fine-structure "constant" $\alpha$ in dS-SR varies with time. By means
of the $t-z$ relation of the $\Lambda$CDM model, $\alpha$'s time-dependency
becomes redshift $z$-dependent. The dS-SR's predictions of
$\Delta\alpha/\alpha$ agree with data of spectra of 143 quasar absorption
systems, the dS-space-time symmetry is SO(3,2) (i.e., anti-dS group) $\;$ and
the universal parameter $R$ (de Sitter ratio) in dS-SR is estimated to be
$R\simeq 2.73\times 10^{12}ly$. The effects of dS-SR become visible at the
cosmic space-time scale (i.e., the distance $\geq 10^9 ly$). At that scale
dS-SR is more reliable than Einstein SR. The $\alpha$-variation with time is an
evidence of SR with de Sitter symmetry.
