Information disclosure is at the core of the registration-based IPO reform. Using the pilot implementation of the registration-based IPO reform on China’s Growth Enterprise Market (GEM) as the research setting, this paper constructs a multi-dimensional measure of information disclosure quality based on accuracy, readability, and completeness, and employs a difference-in-differences (DID) approach to examine the impact of the registration-based system on the quality of information disclosure. The results show that, overall, the registration-based IPO reform improves the quality of IPO firms’information disclosure. A more detailed analysis reveals that the reform enhances readability and completeness but has no significant effect on the accuracy of information disclosure. The positive impacts of the reform on readability and completeness is more pronounced when underwriters have higher reputations and executives receive stronger incentives. Mechanism tests indicate that the reform influences information disclosure quality by strengthening regulatory constraints and enhancing pricing incentives. Further analysis demonstrates that, by improving information disclosure quality, the reform effectively enhances market pricing efficiency and increases IPO firms’long-term post-listing returns. This study contributes to the literature on the effects of implementing the registration-based system implementation and provides empirical evidence and policy insights for further optimizing the reform.