Abstract: Equivalent hydraulic aperture can quantitatively characterize the hydraulic conductivity of rough fractures under Darcy flow conditions, accurately predicting the equivalent hydraulic aperture is of great importance for many practical engineering applications. [Objective]The equivalent hydraulic aperture of rough fractures is influenced by complex geometric features such as wall surface topography and aperture distribution. This study comprehensively consider the geometric information of fractures, use the maximal information coefficient (MIC) method to determine the key controlling factors of the equivalent hydraulic aperture, and establish a characterization model for the equivalent hydraulic aperture of rough fractures based on these key factors. [Methods]First, based on the Barton's 10 standard curves, 900 sets of nonmatching rough fractures were constructed, the geometric information of the wall was used to obtain 13 geometric parameters and the equivalent hydraulic apertures of all fractures were obtained through direct numerical simulations. Then, the maximal information coefficient method was employed to analyze the correlation between the equivalent hydraulic aperture and 13 geometric parameters, [Results]as a result, 4 major controlling factors were identified, based on these factors, a characterization model for the equivalent hydraulic aperture of rough fractures was established. [Conclusion]Based on the data of 900 rough fractures, two existing models for representing the equivalent hydraulic aperture were selected for comparative analysis, the analysis results showed that the hydraulic aperture model proposed in this study exhibited better characterization performance compared to the existing models. Finally, the study investigated the influence of size effects on establishing an equivalent hydraulic aperture representation model, and discussed the methods of extending the research of this paper to three-dimensional fractures.