To enhance regional judicial quality, the Supreme People’s Court of China has been establishing local circuit courts in phases since 2015. This paper utilizes the quasi-natural experiment to empirically examine the impact of improved regional judicial standards on corporate voluntary disclosure. The findings indicate that the establishment of circuit courts significantly reduces the similarity of corporate annual reports, thereby increasing information content and improving the quality of voluntary disclosure. Mechanism testing reveals that circuit courts promote enterprises to improve the quality of voluntary disclosure by addressing local protectionism and exerting deterrent and governance effects. Further investigation shows that this effect is more pronounced in enterprises with initially poorer external governance environments, lower information quality, and higher litigation costs, and positively affects both internal and horizontal similarities in corporate disclosure. Additionally, the establishment of circuit courts helps to mitigate corporate earnings manipulation. This paper not only enriches the literature in the field of “law and finance”, but also provides new perspectives and empirical evidence on judicial reform and its economic consequences.