Hi Sopha Sum, 

In odoo v8 qweb Excel report is out of box. If you want to generate Excel report you need to customize. And this can be done by importing xlsxwriter package. There are built in methods available so it will help you out.

Sample code:

 // .py code

            'filename' : fields.char("File Name", size=64)

            'excel_file' : fields.binary('Excel File')



            filename = "Test.xlsx"

            fp = StringIO()

            workbook = xlsxwriter.Workbook(fp)

            worksheet = workbook.add_worksheet('Report')

            .....



            workbook.close()

            self.write({'excel_file': base64.encodestring(fp.getvalue()), 'filename': filename})

            fp.close()

            return {

                'view_mode': 'form',

                'res_id': self.id,

                'res_model': 'test.test',

                'view_type': 'form',

                'type': 'ir.actions.act_window',

                'context': self.env.context,

                'target': 'new',

            }



// xml code

            <field name="filename" invisible="1"/>

            <field name="excel_file" filename="filename" readonly="1"/>



Reference links http://xlsxwriter.readthedocs.io/