You're doing two separate sorts. Which sorts by the first criteria and then resorts by the second criteria (completely ignoring the first).

If you want to sort by two criteria then you need to do both comparisons in the same sorting block.

use strict;
use warnings;

my @data = (
            {
             vtype_ug => 1,
             total_rate => 400,
            },
            {
             total_rate => 220,
            },
            {
             total_rate => 700,
             vtype_ug => 1,
            },
            {
             total_rate => 300,
            },
            {
             total_rate => 400,
            },
            {
             total_rate => 250,
            },
           );

my @sorted = sort { -(exists $a->{vtype_ug} <=> exists $b->{vtype_ug})
                               ||
                    $a->{total_rate} <=> $b->{total_rate} } @data;

use Data::Dumper;
print Dumper @sorted;
[download]

Note: The negation on the first comparison ensures that elements with "vtype_ug" come before those who don't (without it the order is reversed).