  We study the shadow of a charged rotating black hole in $f(R)$ gravity. This
black hole is characterized by mass, $M$, spin, $a$, electric charge, $Q$ and
$R_{0}$ which is proportional to cosmological constant. We analyze the image of
the black hole's shadow in four types 1) at $r\rightarrow\infty$, 2) at
$r\rightarrow r_{o}$, in vacuum, 3) at $r\rightarrow\infty$, 4) at
$r\rightarrow r_{o}$, for an observer at the presence of plasma. Moreover, we
investigate the effect of spin, charge and modfication of gravity on the shape
of shadow. In addition, we use two observables, the radius $R_{s}$ and the
distortion parameter $\delta_{s}$, characterizing the apparent shape. We show
that for all cases, the shadow becomes smaller with increasing electric charge.
Also, by increasing the rotation parameters, circular symmetry of the image of
black hole's shadow will change. Furthermore, in the presence of plasma, plasma
parameter also effects on size of the shadow.
