您可以通过添加次要定位器（set_minor_locator）到您的代码并将其设置为月份来实现这一点，这将为每个月给予次要报价。更新了以下随机价格的示例代码...

Price = {'Price':np.random.randint(30, size=(20))}
df = pd.DataFrame(Price)
df['Date'] = pd.date_range(start = '2017-01-01', end = '2019-01-01', periods = len(df))

plt.figure(figsize=(10,6))
plt.xlim(datetime.datetime(2017, 1, 1), datetime.datetime(2019, 1, 1))
plt.minorticks_on()

## Add these lines
import matplotlib.dates as mdates
plt.gca().xaxis.set_minor_locator(mdates.MonthLocator()) ## Minor ticks every month

plt.plot(df['Date'], df['Price'])

您可以将set_major_locator和set_minor_locator与matploltib中的MultipleLocator或AutoLocator模块组合使用。

from datetime import datetime
from matplotlib.ticker import (MultipleLocator, AutoMinorLocator)

fig, axs = plt.subplots(figsize=(10,6))
plt.xlim(datetime(2017, 1, 1), datetime(2019, 1, 1))
axs.xaxis.set_major_locator(MultipleLocator(90))

# For the minor ticks, use no labels; default NullFormatter.
axs.xaxis.set_minor_locator(MultipleLocator(9))

多亏了@Redox，我才能想出一个解决方案：

from matplotlib.dates import MonthLocator, YearLocator

plt.figure(figsize=(10,6))
plt.xlim(datetime(2017, 1, 1), datetime(2019, 1, 1))
plt.minorticks_on()

is_label_year = re.match('^\d{4}$', plt.gca().xaxis.get_majorticklabels()[0].get_text())
plt.gca().xaxis.set_minor_locator(YearLocator() if is_label_year else MonthLocator())

plt.plot(df['Date'], df['Price'])

基本上，我有条件地设置YearLocator或MonthLocator，这取决于majorticklabels的格式分别是YYYY还是YYYY-MM。