Arely Gomez Gonzalez released more than 80 volumes of material.
The case has prompted protests across Mexico, increasing pressure on President Enrique Pena Nieto.
Relatives dispute his government's account that police in Guerrero state handed the students over to a gang who killed them and burnt the bodies.
The attorney general's office said the document had taken around 100 investigators seven months to compile.
But an international panel of experts said it had found many flaws in the investigation.
It concluded that the government's account that the students were incinerated beyond identification at a rubbish dump was physically impossible.
It said official reports appeared to downplay the presence of federal police and troops near the areas where the students were seized.
The experts said the army had refused to allow them to interview soldiers.
The attorney general has said her office has not closed the file and will continue to investigate the case.
The Mexican attorney general has made public the file on last year's disappearance of 43 student teachers who clashed with the police.