I want empty search returns to home page in my wordpress

This will do exactly what you’re asking for:

add_action('wp', 'redirect_empty_search');
function redirect_empty_search() {
  global $wp_query;
  if( isset( $_REQUEST['s'] ) && 0 === $wp_query->post_count ) {
    wp_redirect( home_url() );
    exit;
  }
}

You’ll want to add some kind of message on the homepage when this happens, maybe by adding a query parameter to home_url() and displaying a message in your theme when that parameter is set. Something like:

wp_redirect( add_query_arg( 'searchfailed', '1', home_url() ) );