Hi @guox,
The issue description is not imported to eazyBI Issues cube by default. See similar question with possible resolutions here: Import JIRA Issue Description.
Additionally, if you only need to search for a particular value within the description, I would suggest options one or two to extract the word you are looking for from the description into a separate custom field and finally in the eazyBI dimension (see more about JavaScript calculated custom fields).
Lauma / support@eazybi.com