First, your post is extremely difficult to read. It looks like you're missing the </code> tags. I tried reformatting your code and output, which I added at the end of this post.

It looks like you're iterating over the keys of your hash, but not using the keys to look for anything in the array. I think you might need to change the following line:

if(exists $orgin{$val})

to be the following:

if(exists $orgin{$key})

Without knowing the contents of the array and hash, it will be difficult to try to help offer suggestions on what could be wrong with your code.

---

OP's code and output reformatted:

foreach my $key(keys %orgin) {
    #my $tmp_key=quotemeta "$key";
    foreach my $val(@port_list) {
        $val=~s/\s+$//;
        #print "$val***********";
        #my $tmp_val=quotemeta "$val";
        if(exists $orgin{$val}) {
            #print "same key :$tmp_val\n";
            next;
        }
        else {
            print "$val : $key Entered the else loop\n";
            push @{$orgin{$val}}, "xxxx"; $count++;
        }
    }
}
print Dumper \%orgin;
[download]

OUTPUT: $VAR1 = {
    '' => 'xxxx' ,
    ' input' => 'xxxx' ,
    'input' => 'ai400_INH',
    'i50_TXD_p' ,
    'inout' => 'VIORING50',
    'DVCC16', 'VPRE30',
    'VCC50_p',
    'VIO50_p',
    'io50_MISO_p',
    'io50_NCS_p',
    'io50_RXD_p',
    'aio33_atb_0',
    'aio33_atb_3' ,
    'output' => 'ao400_INH_p' ,
    ' inout' => 'xxxx' ,
    'inout 4:0' => 'VIO50' ,
    ' inout 2:0' => 'xxxx' ,
    ' output' => 'xxxx' ,
    ' inout 4:0' => 'xxxx'
};
[download]