行版本可以使用vlines实现，但请注意，使用fill_between可以更好地再现您的参考图。

线路版本

使用支持ymin和ymax边界的vlines代替axvline。
把你的y变成一个lambda f(x, mu, sd)并用它来定义ymax的边界：

# define y as a lambda f(x, mu, sd)
f = lambda x, mu, sd: (1 / (sd * (2*np.pi)**0.5)) * np.exp((-(x-mu)**2) / (2*sd**2))
fig, ax = plt.subplots(figsize=(8, 3))
x = np.linspace(148, 200, 200)
mu = 178
sd = 5
ax.plot(x, f(x, mu, sd))
# define 68/95/99 locations and colors
xs = mu + sd*np.arange(-3, 4)
colors = [*'yrbgbry']
# draw lines at 68/95/99 points from 0 to the curve
ax.vlines(xs, ymin=0, ymax=[f(x, mu, sd) for x in xs], color=colors)
# relabel x ticks
plt.xticks(xs, [f'${n}\sigma$' if n else '0' for n in range(-3, 4)])

阴影版本

使用fill_between可以更好地重新创建示例图形。使用where参数定义着色边界：

fig, ax = plt.subplots(figsize=(8, 3))
x = np.linspace(148, 200, 200)
mu = 178
sd = 5
y = (1 / (sd * (2*np.pi)**0.5)) * np.exp((-(x-mu)**2) / (2*sd**2))
ax.plot(x, y)
# use `where` condition to shade bounded regions
bounds = mu + sd*np.array([-np.inf] + list(range(-3, 4)) + [np.inf])
alphas = [0.1, 0.2, 0.5, 0.8, 0.8, 0.5, 0.2, 0.1]
for left, right, alpha in zip(bounds, bounds[1:], alphas):
    ax.fill_between(x, y, where=(x >= left) & (x < right), color='b', alpha=alpha)
# relabel x ticks
plt.xticks(bounds[1:-1], [f'${n}\sigma$' if n else '0' for n in range(-3, 4)])

要标记区域百分比，请在有边界区域的中点处添加text对象：

midpoints = mu + sd*np.arange(-3.5, 4)
percents = [0.1, 2.1, 13.6, 34.1, 34.1, 13.6, 2.1, 0.1]
colors = [*'kkwwwwkk']
for m, p, c in zip(
    midpoints, # midpoints of bounded regions
    percents,  # percents captured by bounded regions
    colors,    # colors of text labels
):
    ax.text(m, 0.01, f'{p}%', color=c, ha='center', va='bottom')