This question is an exact duplicate of:
How do I export map information display styles from ArcGIS Desktop to QGIS?
I tried exporting MXD to QGS (using mxd2qgs) - but the styles were not saved;Also, when I try to export styles from arcgis to SLD format (using ArcGIS_SLD_Converter) and finally got:
"Index outside the range."
The index should be a positive number, and its size should not exceed the size of the collection Parameter name: index in System.collections.ArrayList.get.item (lnt32 index) in ArcGis_SLD_Converter.Output_SLD.WriteToSLD()"