XML is an important standard of information exchange and representation on the Web. Analysis of data on the Web requires data analysis techniques of XML data. With tags representing semantics, XML data has more complex structure than relational database. Therefore, analysis of XML data can be more flexible. In this paper, concepts of XOLAP, OLAP of XML data, are presented. In order to supporting XOLAP, a general aggregation operator of XML, GXaggregation, is presented. Based on GXaggregation, XCube, an extension of tradition cube operator, is defined on XML data model. These operators can be embedded into XML query languages such as XQuery. In this paper, definitions and expressions operators related to XOLAP are presented, as well as a primary implementation of GXaggregation and XCube