>>> import matplotlib.pyplot as plt
>>> plt.plot([1,2,3])
[<matplotlib.lines.Line2D object at 0x01B4B1D0>]
>>> plt.title(u'Прямая линия')
<matplotlib.text.Text object at 0x01B5DC90>
>>> plt.show()

>>> import matplotlib as mpl
>>> import matplotlib.pyplot as plt
>>> mpl.rcParams['font.sans-serif'] = 'DejaVu Sans'
>>> plt.plot([1,2,3])
[<matplotlib.lines.Line2D object at 0x01D003B0>]
>>> plt.title(u'Прямая линия')
<matplotlib.text.Text object at 0x01D14250>
>>> plt.show()

import os
import matplotlib.font_manager as fm
import matplotlib.pyplot as p


p.rcParams['text.usetex'] = False
path_to_skript =  os.path.abspath(__file__)
path_to_skript = os.path.split(path_to_skript)[0]
fp1 = fm.FontProperties( fname = os.path.join(path_to_skript, 'arial.ttf' ))

...

figure = p.figure()
ax1 = figure.add_subplot(211)
ax1.set_title(u'Четные корни', fontproperties = fp1)
ax1.set_ylabel(u'Ось y', fontproperties = fp1)

Traceback (most recent call last):
  File "C:/Documents and Settings/kyzic/Рабочий стол/1.py", line 7, in <module>
    path_to_skript =  os.path.abspath(__file__)
NameError: name '__file__' is not defined

figure = p.figure()
ax1 = figure.add_subplot(211)
ax1.set_title(u'Четные корни', fontproperties = fp1)
ax1.set_ylabel(u'Ось y', fontproperties = fp1)