Fatima Elomar, 31, pleaded guilty to providing support for Islamic State (IS) during a brief appearance at Sydney's Downing Centre district court, ABC reported.
She was arrested by counter-terrorism officials in May 2014, as she tried to board a flight to Malaysia with her four children.
Counter-terrorism police said Fatima was carrying cash, camouflage equipment and medical supplies at the time.
Her husband is believed to have been killed while fighting in Iraq in June, along with fellow Australian IS recruit Khaled Sharrouf.
The court heard, in messages exchanged between the couple, she asked him what she would need in Syria. He replied she would need heavy duty socks, hiking shoes for both herself and the children, solar powered torches, thermals and solar power charges.
Mohamed Elomar also asked her to bring with her a shaver and a waterproof jacket.
Court documents also showed images were exchanged between the pair, including one of Mohamed Elomar using crutches and another of Sharrouf's sons dressed in camouflage and holding a hand gun.
Mohamed Elomar's postings on social media indicated he was a popular and influential figure among Australians who turned up to fight for IS.
An Australian police warrant was issued for his arrest last year, but he had long professed a desire to die in battle.
He was also accused of enslaving women from the Yazidi religious minority in northern Iraq.
The government estimated in September that around 120 Australians were currently in Iraq and Syria to support IS and other terror groups.