Clad in academic gown and hat, Mugabe walked slowly in a procession on a red carpet to a podium as a marching band played.
Several thousand graduates of the Zimbabwe Open University and guests stood as Mugabe and other dignitaries entered a tent set up for the event.
Once on the podium, Mugabe joined the crowd in singing Zimbabwe's national anthem. He announced the opening of the graduation ceremony, and the crowd applauded.
Mugabe's presidential security detail was present.
More From This Section
The appearance comes during an extraordinary series of negotiations with regional leaders over Mugabe's departure after 37 years in power.
The military is taking pains to show respect for the 93- year-old leader, the world's oldest head of state, by referring to him as the president and the commander-in-chief.
Today's event appears to allow Mugabe to project the image of leadership, even as calls for his departure grow stronger.
Zimbabwe's military says it is continuing talks with President Robert Mugabe for his departure while it pursues those who were close to the leader and his wife.
The Zimbabwe Defence Forces said "significant progress has been made in their operation to weed out criminals around President Mugabe," adding that they had arrested some although others were still at large.
The statement said Zimbabwe's military is "currently engaging with the Commander-in-Chief President Robert Mugabe on the way forward and will advise the nation of the outcome as soon as possible." The state Zimbabwe Broadcasting Corporation television aired a similar report in its early morning bulletin.