Former NBA star Trevor Ariza told the court about his financial situation as part of his legal battle with his ex-wife, Bree Anderson Ariza ... and it's a far cry from what he was making as a player.

TMZ obtained an income and expense declaration filed by Trevor, which states he earns an average of $6,000 per month as a trainer for the disabled … but says he only made around $2,316 last month.

He also claims he earns around $667 per month from investments in Buffalo Wild Wings. He said he has around $50K in cash and bank accounts … and $2.5 million in real property.

Trevor said he lives with his girlfriend, Kristy, and her two kids ... along with his 14-year-old son and his aunt.

He lays out his monthly expenses, which include $2K on healthcare, $2K on groceries, $2K on utilities, $500 on cleaning and laundry, $2K on education, $500 on clothes, and $2K on auto expenses and insurance. His total monthly expenses come to $11,600 -- which would be less than he says he brings in each month. He also claims he paid $7,700 in child support for children from other relationships.