Large amounts of documents are exchanged during the construction phase of projects, which covers the important management information. To utilize the exchanged documents to support decision-making of the management staffs, the requirement analysis was carried out based on the interviews to the practitioners. A decision support system called Explyzer+ was developed based on the previous prototype system Explyzer. The latter was enhanced by adding the functions to automate the whole process and the techniques of data mining including decision tree analysis and clustering analysis. A case study for in-depth information analysis was conducted based on the data obtained from a large construction project to demon-strate its feasibility and effectiveness. The system could effectively assist the management staffs to carry out in-depth information analysis for decision-making in construction projects.