Spreadsheet is one of the most widely used programming tool because of its ease of use, however there have been few researches on applying object-oriented techniques in developing spreadsheet applications. Generally, spreadsheet applications contain a lot of errors, and spreadsheet has some drawbacks such as low reusability and hard maintenance. In order to solve these problems, we introduce an object-oriented spreadsheet system, named XCEL. It enables users to develop applications using systematic techniques with data modelling method, and allows users to apply object-oriented technologies to spreadsheet programming. The data modelling method allows to define classes using XML and flowchart, and the spreadsheet represents an object with contiguous cells. XCEL has advantage that users can apply object-oriented technology to spreadsheet programming.