#构造数据
vals1 = [1, 2, 3, 4]
vals2 = [2, 3, 4, 5]
vals3=[1]
fig, ax = plt.subplots()
labels = 'A', 'B', 'C', 'D'

#最外层的圆
ax.pie(vals1, radius=1.2,autopct='%1.1f%%',pctdistance=0.9,colors=['r','g','b','c'],shadow=False)

#中层的圆
ax.pie(vals2, radius=1,autopct='%1.1f%%',pctdistance=0.75,colors=['r','g','b','c'],shadow=True)

#最里层的圆
ax.pie(vals3, radius=0.6,colors='w')
ax.set(aspect="equal", title='Pie plot with `ax.pie`')

#图例
plt.legend(labels,bbox_to_anchor=(1, 1), loc='best', borderaxespad=0.)
plt.show()