The Nobel laureate said that that the army is duty-bound to safeguard the country and should not be involved in running the administration.
Her comments during a rally in the second largest city of Mandalay drew loud cheers.
Myanmar started moving from a half century of dictatorship to democracy three years ago, but the army still lurks heavily in the shadows.
The 2008 constitution drawn by the former military rulers gives the army 25 per cent of all parliamentary seats, allows it to appoint three cabinet ministers and have veto power in changing the constitution.
An article in the constitution says anyone whose spouse or children owes allegiance to a foreign power cannot become president or vice president. Suu Kyi's sons are British nationals.
Several other provisions are also under scrutiny for revision, and some proposed changes would strengthen self-government in regions of the country dominated by ethnic minorities.