FAQ: Does ArcMap Server support field alias set in ArcMap?
Does ArcMap Server support field alias set in ArcMap?
No; field alias set in the ArcMap document is dropped when the document is served. The original field names are used.
Field alias can be set when creating a Java Web site. It can also be set by clients, such as ArcMap, that allow for this functionality.
In ArcIMS 9.2 GET_FEATURES requests made to Arcmap services with outputmode="newxml" will return field aliases set in the ArcMap document as part of query response. However you will not be able to query using a field alias name.