Thank you for your response. You are right. After I installed python packages xlwt/xlrd, the ExportImportXlsPlugin installed to trac. The Export function of the plugin work ok, but Import function not work very well. The TicketImportPlugin works better. In fact it only needs the TicketImportPlugin. Trac has the export function. Look at the bottom of ticket page, "download in other formats", then select comma-delimited text, it will generate a csv file. Modify the csv file: delete the id or ticket column. Then use the import function. The ticket file will transfer to your project.