Keyword view displaying all the recorded objects in hierarchical fashion and expert view displaying the information in the form of VB Script. If you perform any modifications in Keyword view it reflects in expert view and vice versa.
QTP's Keyword Driven approach, test automation experts have full access to the underlying test and object properties, via an integrated scripting and debugging environment that is round-trip synchronized with the Keyword View. Advanced testers can view and edit their tests in the Expert View, which reveals the underlying industry-standard VBScript that QuickTest Professional automatically generates. Any changes made in the Expert View are automatically synchronized with the Keyword View.