The Korean government released the National Spatial Data Infrastructure Portal (NSDIP) by integrating the spatial information possessed by 205 agencies to implement governance through the portal. In this study, four evaluation criteria groups (disclosure, participation, civil petition service, and website usability) were established through a literature review related to governance and government portals. After evaluation based on the four evaluation criteria, governance improvement measures were suggested. As an improvement measure, in terms of information disclosure, it was necessary to manage the quality of data update cycle, accuracy, metadata, etc., and to provide customized spatial information. In the stakeholder participation section, feedback from users is reflected in policies, and activation of participation spaces through education and exhibitions is required. In terms of civil petition service, it is necessary to introduce an incentive system to improve innovative services and to prepare measures to prevent infringement of security and privacy in the civil petition process. In website usability, it is necessary to prepare an improvement plan by introducing user-friendly interface design using GIS viewer, and statistics and GIS spatial analysis functions. The improvement plan by the evaluation criteria is expected to be the direction to implement inclusive portal governance.