Prosecutors accuse Ronaldo, reported to be the world's highest paid athlete, of evading €14.7m ($17.3m; £13.1m) in tax.
He had been expected to make a statement after the pre-trial hearing, but left without saying a word.
The Real Madrid star, 32, has previously denied the allegations, saying his "conscience is clear".
Ronaldo, 32, is the latest in a string of footballers to be pursued by the Spanish tax authorities.
Argentina's Lionel Messi, who plays for Barcelona, was handed a 21-month prison sentence after being found guilty of the same charge last year.
Earlier this month, the court ruled he could pay €252,000 in place of jail time.
However, Messi was only accused of evading €4.1m in tax, €10.6m less than Ronaldo.
Ronaldo spent an hour-and-a-half giving evidence to judges at a court in the Madrid suburb of Pozuelo de Alarcón on Monday.
The media had gathered on the court steps in front of a lectern and speakers, set up by Real Madrid in anticipation of a speech by the footballer.
But Ronaldo avoided journalists by arriving and leaving via an underground garage.
BBC Sport's Richard Conway said Ronaldo had been expected to strike a "defiant tone", but instead decided to go straight home, earning him a chorus of boos from the gathered press.
According to prosecutors, Ronaldo allegedly took "advantage of a company structure created in 2010 to hide income generated in Spain from his image rights from tax authorities", which was a "voluntary and conscious breach of his fiscal obligations in Spain".
Ronaldo's management has also denied the allegations.
But if the case is sent to trial and he is found guilty, the Portuguese forward could face a fine of "at least €28m" and a prison sentence of three-and-a-half years, the Gestha union of experts at Spain's Inland Revenue says.