I am using Virtue mart 3.0.18.
I want to hide the Review tab on Product Details page.
I have already uncheckes the Auto Publish Review option from configuration page.
Please help me to solve this issue.
You don't give a url or state which template you use, but in default VM templates setting all options in config/shopfront/Shopper Review/Rating System to Don't show or Disabled stops the review options from being shown on product details.
So, assuming that you have a non-standard VM template that does not follow VM rules you probably need to edit and override templates/[your-joomla-template]/html/com_virtuemart/productdetails/tmpl/default.php or templates/[your-joomla-template]/html/com_virtuemart/productdetails/tmpl/default_reviews.php