  We report the large linear magnetoresistance ($\sim 300\%$ in 9 T field at 2
K) and magnetothermopower in layered SrZnSb$_2$ crystal with
quasi-two-dimensional Sb layers. A crossover from the semiclassical parabolic
field dependent magnetoresistance to linear field dependent magnetoresistance
with increasing magnetic field is observed. The magnetoresistance behavior can
be described very well by combining the semiclassical cyclotron contribution
and the quantum limit magnetoresistance. Magnetic field also enhances the
thermopower. Our results can be well understood by the magnetotransport of
Dirac states in the bulk band structure.
