Can I deduct my $500 payment to my exwife from my pension. We do have a order with a court.

[Vanessa]

Possibly, it depends on a few more things. If it meets all of the requirements below to be considered alimony then yes.  Also, the order would have had to be made prior to December 31, 2018.  

"Alimony Requirements

A payment is alimony only if all the following requirements are met:

• The spouses don't file a joint return with each other;
• The payment is in cash (including checks or money orders);
• The payment is to or for a spouse or a former spouse made under a divorce or separation instrument;
• The divorce or separation instrument doesn't designate the payment as not alimony;
• The spouses aren't members of the same household when the payment is made (This requirement applies only if the spouses are legally separated under a decree of divorce or of separate maintenance.);
• There's no liability to make the payment (in cash or property) after the death of the recipient spouse; and
• The payment isn't treated as child support or a property settlement.

Payments Not Alimony

Not all payments under a divorce or separation instrument are alimony. Alimony doesn't include:

• Child support,
• Noncash property settlements, whether in a lump-sum or installments,
• Payments that are your spouse's part of community property income,
• Payments to keep up the payer's property,
• Use of the payer's property, or
• Voluntary payments (that is, payments not required by a divorce or separation instrument)." https://www.irs.gov/taxtopics/tc452