设置字体后，就能够正常显示汉字
plt.rcParams['font.family'] = ['Microsoft YaHei']
例子：
import matplotlib.pyplot as plt
import matplotlib.font_manager as fm
# 设置字体
plt.rcParams['font.sans-serif'] = ['Microsoft YaHei']
temps=[23,22,23,24,27,28,25,23]
hours=list(range(2,26,3))
plt.plot(hours,temps)
plt.title('气温变化情况',fontsize=18)
# 显示
plt.show()