  Two eclipsing binary systems UZ Lyr and BR Cyg are the semi-detached types
whose secondary component fill its Roche lobe. Although radial velocity and
light curves of these systems have already been investigated separately, both
radial velocity and light curves of them are analyzed simultaneously for the
first time in the present study . Also, the orbital period changes of these
systems are studied. Our results show that the mass transfer between components
have negligible effects on the orbital period changes of these systems, but two
light-time effects are the reasons of the periodic behavior of the O-C curve
for UZ Lyr. We could not remark more information about orbital period changes
for BR Cyg, but we find a new orbital period for it. By radial velocity and
light curves analysis we find a clod spot on the secondary components of BR
Cyg. The new geometrical and physical parameters of both systems are obtained
and their positions on H-R diagram demonstrated.
