How does the establishment of the National Supervisory Commission affect China's capacity to curb corruption? Using published materials and fieldwork data, this article addresses this question by comparing the newly established anti-corruption agency with the previous dual-track system. It first examines the previous system by focusing on four dimensions of the interaction between the Commission for Discipline Inspection (CDI) and the People's Procuratorate: complementarity, convergence, competition and conflict. Although the CDI and the procuratorate compensated for each other's deficiencies, competition and conflicts between the two institutions were rife, reducing the efficiency of China's anti-corruption work. The article then investigates what impact the establishment of the National Supervisory Commission has had on China's capacity to combat corruption. This new model strengthens the Party's capacity to curb corruption, and the focus of the anti-corruption work has shifted from punishment to prevention, but the Party still needs to resolve three types of unbalanced power relations: between supervision, prosecution and trial; between central and local authorities; and between the state and citizens.