您正在比较字符串。您应该比较日期时间/日期对象

You are comparing strings. You should compare datetime/date objects

import datetime
TODAY_CHECK = datetime.datetime.now()
start = datetime.datetime.strptime("26-11-2017", "%d-%m-%Y")
end = datetime.datetime.strptime("30-11-2017", "%d-%m-%Y")
if start <= TODAY_CHECK <= end:
    print "PASS!"
else:
    print "YOU SHALL NOT PASS, FRODO."

或者您可以这样做

start = datetime.datetime(day=26,month=11,year=2017)
end = datetime.datetime(day=30,month=11,year=2017)