只需要使用ax.add_patch(Ellipse(...))就可以了。例如：

import matplotlib.pyplot as plt
from matplotlib.patches import Ellipse

# create some data
x = np.arange(-8., 8.)
array = np.exp(-(x ** 2 + x[:, None] ** 2) / 30)
array += 0.5 * np.random.random(array.shape)

# draw the image
implot = plt.imshow(array, cmap='gist_heat',interpolation="none")
plt.colorbar(implot, orientation='vertical')

# draw the ellipse
ax = plt.gca()
ax.add_patch(Ellipse((8, 8), width=8, height=6,
                     edgecolor='white',
                     facecolor='none',
                     linewidth=5))