Why .htaccess does not work

Last Friday, I put an .htaccess file into one folder of my site. The function of this htaccess is to make it auto redirect to other path.
The problem is it is not working. I do have use this kind of code many times. Why it does not work any more?
It looks the Apache works like there is no this .htaccess file here. I think it must be something wrong in my httpd.conf setting.
After double checking with Apache tutorial, I found the answer.


The troubleshooting said:

When you put configuration directives in a .htaccess file, and you don’t get the desired effect, there are a number of things that may be going wrong.
Most commonly, the problem is that AllowOverride is not set such that your configuration directives are being honored. Make sure that you don’t have a AllowOverride None in effect for the file scope in question. A good test for this is to put garbage in your .htaccess file and reload. If a server error is not generated, then you almost certainly have AllowOverride None in effect.

So add AllowOverride ALL make it work.