Export the external list to Excel
Navigate to the SharePoint site that contains the list.
Click the name of the SharePoint list on the Quick Launch, or on the Settings menu Office 365 Settings button , click Site contents or View All Site Content, and then in the appropriate list section, click the name of the list.
Click List and then click Export to Excel.
By default, this capability is enabled on external lists, but it can be disabled by a system administrator.
If you are prompted to confirm the operation, click OK.
In the File Download dialog box, click Open.
If you are prompted whether to enable data connections on your computer, click Enable if you believe the connection to the data on the SharePoint site is safe to enable.
An Excel Table is created with a data connection based on a web query file. The columns in the exported table are determined by the current external list view. The external data exported is determined by the filters defined on the external content type and in the external list view, and the language settings for the SharePoint site. Any page limits are ignored.
Export an external list to Excel