Hello Steveguo!

There maybe 2 points:

1) You haven't uploaded .htaccess file in the root of UNA directory. You may get it from here https://github.com/unaio/una/blob/master/.htaccess

2) You server hasn't the installed modrewrite module which is one of UNA's requirements. So, in this case, you need to contact with your hosting support to install / enable it.