She was arrested in November 2011 after trying to leave the country to seek medical treatment.
Mrs Arroyo is accused of rigging a 2007 election in favour of her candidates.
Prosecutors say she helped a powerful local clan leader rig senatorial elections in a southern region where 12 candidates she backed swept to victory.
The poll rigging charge is the first of several cases expected to be brought against her.
The trial is seen as a landmark case in the country and a test for her successor, President Benigno Aquino III, a reformist who has promised to weed out corruption.
Mrs Arroyo insists that Mr Aquino is waging a personal vendetta against her, says the BBC’s correspondent in Manila, Kate McGeown.
If convicted Mrs Arroyo, who was president from 2001 to 2010, could face life in prison. But it could be some time before the verdict is known.
Trials in the Philippines take a long time, says our correspondent. Mrs Arroyo’s predecessor Joseph Estrada’s trial for corruption lasted six years.