核心方法是：

s = df.columns.to_series()
df.columns = s.map(dic).fillna(s)

使用示例

import pandas as pd

if __name__ == '__main__':
    df = pd.DataFrame([
        [0, 1, 1],
        [0, 1, 1],
        [0, 2, 2],
        [0, 2, 3]
    ], columns=['a', 'b', 'c'])
    dic = {'a': '1', "b": "2"}
    s = df.columns.to_series()
    df.columns = s.map(dic).fillna(s)
    print(df.columns.tolist())

结果：['1', '2', 'c']