<?php

$taxonomy = ‘product_cat’;
$orderby = ‘name’;
$show_count = 0; // 1 for yes, 0 for no
$pad_counts = 0; // 1 for yes, 0 for no
$hierarchical = 1; // 1 for yes, 0 for no
$title = ”;
$empty = 0;

$args = array(
‘taxonomy’ => $taxonomy,
‘orderby’ => $orderby,
‘show_count’ => $show_count,
‘pad_counts’ => $pad_counts,
‘hierarchical’ => $hierarchical,
‘title_li’ => $title,
‘hide_empty’ => $empty
);
$all_categories = get_categories( $args );
foreach ($all_categories as $cat) {
if($cat->category_parent == 0) {
$category_id = $cat->term_id;
echo ‘<br /><a href=”‘. get_term_link($cat->slug, ‘product_cat’) .‘”>’. $cat->name .‘</a>’;

$args2 = array(
‘taxonomy’ => $taxonomy,
‘child_of’ => 0,
‘parent’ => $category_id,
‘orderby’ => $orderby,
‘show_count’ => $show_count,
‘pad_counts’ => $pad_counts,
‘hierarchical’ => $hierarchical,
‘title_li’ => $title,
‘hide_empty’ => $empty
);
$sub_cats = get_categories( $args2 );
if($sub_cats) {
foreach($sub_cats as $sub_category) {
echo $sub_category->name ;
}
}
}
}
?>

This will list all the top level categories and subcategories under them hierarchically. do not use the inner query if you just want to display the top level categories. Style it as you like.