It was passed on Thursday night with 156 MPs voting for the Bill and 65 against, reports the Daily Financial Times newspaper.
With support from seven MPs from minorities and main Opposition Samagi Jana Balawegaya (SJB) Assistant Secretary MP Diana Gamage, the government secured the two-third majority in the 225-member Legislature.
The constitutional amendment which would strengthen the hand of the Executive and restore the powers that were stripped from the President under the 19th Amendment to the Constitution.
One of the notable absentee from Thursday night's vote was former President Maithripala Sirisena, one of the main proponents of the 19th Amendment.
The vote came following two days of debate on the Bill which has been strongly opposed by opposition lawmakers, members of the Buddhist and Catholic/Christian clergy, and civil society groups.
Justice Minister Ali Sabry said the government would introduce a new Constitution within the next year and that it would be one that builds national unity and consensus among all communities, the Daily Financial Times newspaper reported.
The Bill will become law once Speaker Mahinda Yapa Abeywardena certifies it inclusive of the amendments.