webform submission won't work if a webform node is set as drupal front page

Webform should work as the homepage node, afaik. However I haven't tried this out myself. Could you double-check the version on this issue to match the version of Webform you're running? In the Webform 3.x branch, 3.18 is the latest release.

I tried this out, but nothing unusual happened. After submitting a form that was set as the site homepage, the webform redirected me to the path node/[nid]/done?sid=[sid], which is to be expected. The confirmation message was displayed, the submission saved, and e-mail sent. So it looks like everything behaves the way it should. When you say, "the webform submission is not work anymore", what do you mean? Do you get an error? Are you redirected at all? Does the page reload? Or when you click the button does nothing happen at all?

Please reopen if this problem can reproduced on your site, or preferably on a clean install of Drupal. Closing after lack of activity.