  In this work, we study the shadow of Kerr black hole surrounded by an
axisymmetric plasma, whose density takes a Gaussian distribution in the polar
direction. Along the radial direction, we consider two models: in model A the
density of the plasma decays in a power law; in model B the density obeys a
logarithmic Gaussian distribution. Using the numerical backward ray-tracing
method, we find that the size of the shadow is sensitive to the inclination
angle of the observer due to the polar distribution of the density of the
plasma. In particular, we pay special attention to the model B and investigate
the influence of the radial position of maximum density, the decay rate of the
density towards the event horizon and the opening angle of the plasma on the
shape and size of the Kerr black hole shadow. The effects of the plasmas
studied in this work can be qualitatively explained by taking the plasmas as
convex lenses with the refractive index being less than $1$.
