Following the Constitutional Revolution up to 1921, Majlis was defeated to materialize the political demands of the reformists and constitutionalists due to the lack of effective executive system and pressure as well as influence of foreigners (Russia and Great Britain) or the internal reactionaries who opposed to constitution.After 1921, however, Reza Shah restored order and established the authority of the centeral government throughout the country, so the appropriate conditions were provided to permit the ratification of the bills and legislations which caused executive and judiciary affairs to be properly materialized.Many noteworthy laws passed in parliaments during the early years in the reign of Pahlavi, the First. This period can be cosidered as an evolution in legislative which culminated in such phase of progress, but after the elapsing these years, Reza Shah disclosed he was a despotic ruler and made the Majlis and representatives to be under his sovereignty. The members of parliament, therefore, had no authority and had to be merely obedient, apparently it was pretended Iran is a constitutional and democratic country and Majlis is independent. But on the contrary it had actually no authority. Without declaration on war, on 25th August 1941, the Western Allies invaded Iran. In the wake of invasion, Reza Shah abdicated in favour of his son and left his homeland never to return. The obstruction of freedom of speech and dicatorship removed and parliament regained the authority to approve or disapprove, independently, the submitted bills or laws.This article is intended to study the causes and necessities of the ratification of bills or laws in Majlis from the fourth term to the thirteenth term, in addition to clarify their abrogation.