The court sentenced Suu Kyi on charges of breaching the terms of her house arrest after a bizarre incident in which an American man, John Yettaw, 54, swam to her lakeside house in May 2009.
The BBC and other foreign news agencies quoted Burmese Home Minister General Maung Oo, as saying outside the court that military ruler Than Shwe had signed a special order suspending the sentence and ordered that Suu Kyi should spend 18 months under house arrest.
Yettaw was sentenced to seven years' imprisonment and hard labour. It includes three years for breaching security laws, three years for immigration violations and one year for a municipal charge of illegal swimming.
Suu Kyi has spent nearly 14 of the past 20 years in detention, and had denied the charge but said she expected to be convicted.