  OO Dra is a short-period Algol system with a $\delta$ Sct-like pulsator. We
obtained time-series spectra between 2016 February and May to derive the
fundamental parameters of the binary star and to study its evolutionary
scenario. The radial velocity (RV) curves for both components were presented,
and the effective temperature of the hotter and more massive primary was
determined to be $T_{\rm eff,1}$ = 8260 $\pm$ 210 K by comparing the
disentangling spectrum and the Kurucz models. Our RV measurements were solved
with the $BV$ light curves of Zhang et al. (2014) using the Wilson-Devinney
binary code. The absolute dimensions of each component are determined as
follows: $M_1$ = 2.03 $\pm$ 0.06 M$_\odot$, $M_2$ = 0.19 $\pm$ 0.01 M$_\odot$,
$R_1$ = 2.08 $\pm$ 0.03 R$_\odot$, $R_2$ = 1.20 $\pm$ 0.02 R$_\odot$, $L_1$ =
18 $\pm$ 2 L$_\odot$, and $L_2$ = 2.0 $\pm$ 0.2 L$_\odot$. Comparison with
stellar evolution models indicated that the primary star resides inside the
$\delta$ Sct instability strip on the main sequence, while the cool secondary
component is noticeably overluminous and oversized. We demonstrated that OO Dra
is an oscillating post-mass transfer R CMa-type binary; the originally more
massive star became the low-mass secondary component through mass loss caused
by stellar wind and mass transfer, and the gainer became the pulsating primary
as the result of mass accretion. The R CMa stars, such as OO Dra, are thought
to have formed by non-conservative binary evolution and ultimately to evolve
into EL CVn stars.
