In the process of comprehensively deepening reform，the People’s Congress undertakes the responsibility of promoting major reform initiatives and solidifying significant reform achievements. This study takes the legislative process of the Beijing Municipal Regulations on Immediate Action on Request as an example，examines the textual development trajectory of draft regulations at different legislative stages through quantitative text analysis，and combines participatory observation to reveal the interaction between the rule of law and reform in the process of the regulations’ transformation from a policy document to a law. It shows that top-down promotion from the high-level and consensus of all parties to consolidate the reform achievements vigorously promote legislative agenda-setting. The legislative process of the Regulations is more reflected in the gradual convergence of divergence and consensus-building among stakeholders. Deputies，the general public，and grassroots staff have more extensive influence on draft text improvement at the deliberation stage of the Municipal People’s Congress. Moreover，text analysis based on digital trace and algorithm-assisted technology vividly reveals three crucial characteristics of the Regulations：the people-centered law serving the people，the reform law of party construction leading the capital grassroots governance，and the original law of Beijing with originality and leadership.