这符合我的要求:

import csv

with open('C:/Path/InputFile.csv', 'rb') as fin, \
     open('C:/Path/OutputFile.txt', 'wb') as fout:
    reader = csv.DictReader(fin)
    writer = csv.DictWriter(fout, reader.fieldnames, delimiter='|')
    writer.writeheader()
    writer.writerows(reader)