Python:Read Multi Csv File as one dataFrame

import pandas as pd
import os
inputdir=r'C:\Users\数据\Desktop\新建文件夹'
df_empty=pd.DataFrame(columns=['名称','列1','列2'])
for parents, dirnames, filenames in os.walk(inputdir):
    for filename in filenames:
        df=pd.read_excel(os.path.join(parent,filename))
        df_empty=df_empty.append(df,ignore_index=True)