Suu Kyi's attendance is viewed as a sign of her improving relations with the military since she was released from house arrest, the BBC said.
She was previously a strong critic of the military's grip on Myanmar, but is now making strides to improve her relationship with the armed forces, which still holds an automatic quarter of the parliament seats.
The parade and Armed Forces Day mark the 68th anniversary of Myanmar's uprising against Japanese rule and more than 6,000 troops were in attendance, the BBC said.
At the parade, Army Chief General Min Aung Haling addressed the recent anti-Muslim clashes in central Myanmar that have led to 40 deaths.
"Our independence came from all Burmese people, including every ethnic minority -- therefore we have to protect it," he said. "The conflict that is going on now, the army never wants that to happen again."
The violence broke out after an argument at a shop last week, which sparked further clashes between Buddhists and Muslims in central Myanmar.