The Portuguese striker is expected to plead guilty after he struck a deal last year with authorities in Spain to settle the case by paying an 18.8 million euro ($NZ30.4m) fine and accepting a suspended jail sentence.
The 33-year-old Juventus forward is unlikely to serve any time in jail, as the 23-month term prosecutors have requested is within a two-year threshold that can be served on probation for a first offence under Spanish law.
Ronaldo asked for special security measures for accessing the court, but the request was denied, a Madrid judge said in a statement. Spanish media reported he had asked to be allowed to enter the courtroom via the car park.
Officials say Wednesday's hearing will be short, and only require Ronaldo to confirm he accepts the deal.