"As head of state I subordinate myself to the powers of this constituent assembly," he said during his address.
"I come to recognize its plenipotentiary powers, sovereign, original and magnificent," he said.
The recent election of the 545-member assembly drew international condemnation for usurping the authority of Venezuela's opposition-controlled Congress. Critics have said the election cast aside any remaining checks on Maduro's power.
Maduro has said the assembly is the country's only chance at securing peace and prosperity after four months of unrest and anti-government protests that have left more than 120 people dead.
In its first working session Aug. 5, the assembly confirmed opposition fears that it would seek to strengthen Maduro's grip on power by firing his main critic within the ruling socialist coalition, chief prosecutor Luisa Ortega. She has been ordered to stand trial.
Maduro's human rights ombudsman, Tarek Saab, was chosen to replace Ortega. The opposition has accused Saab of turning a blind eye to government abuses.
"This assembly had a violent birth," Maduro said during Thursday's address. He drew a standing ovation when he promised that violent anti-government protesters would be jailed.
The opposition boycotted the July 30 election of the assembly and called for an early presidential vote that it was sure Maduro would lose for having presided over a severe economic recession that has been accompanied by shortages of food and medicine.