You can use matplotlib’s
ListedColormap
as follows:

import numpy as np
import seaborn as sns
from matplotlib.colors import ListedColormap

data = np.random.randint(-1, 2, (10,10)) # Random [-1, 0, 1] data
sns.heatmap(data, cmap=ListedColormap(['green', 'yellow', 'red']), annot=True)

which yields:

您可以将字符串“green”、“yellow”、“red”替换为诸如“#FF0000”（相当于“red”）或rgb颜色，如（1,0,0.）`（也可以是相当于“红色”。