Frank Mulholland QC led a delegation of Scottish and US law enforcement officers and prosecutors to Tripoli this week.
It followed the announcement by the Libyan Attorney General that he had appointed two prosecutors to the case.
The visit was a chance for them to meet their Scottish and US counterparts.
Mr Mullholland said there was a commitment from the Libyan authorities to progress the investigation.
"Requests for assistance in the investigation have been made to the Libyan authorities and information has been provided to the Libyan prosecutors to assist them in their understanding of the case," he added.
"Discussions focussed on the need for a framework of co-operation in terms of mutual legal assistance and the Libyan criminal procedure code.
"It was agreed that there will be regular meetings to assess developments and progress."
The bombing of Pan Am flight 103 over Lockerbie claimed 270 lives on 21 December 1988.
Libyan Abdelbaset al-Megrahi was the only person to be convicted of the bombing.
He died in 2012 after being released from prison on compassionate grounds.
The Lord Advocate has said meetings with senior members of the Libyan congress to discuss the Lockerbie bombing case were "extremely positive".