how to copy from excel to outlook and keep the format?

I assume you mean pasting Excel data into email body.

1) In order to not mess formats I select part of the sheet I want to copy, classic Ctrl+C and use special paste in Outlook 2010, ie. right click and choose paste as 'picture'. Usually works ok, but if not:

2) Alternatively you can try another copy mode (Excel 2010+). Select range in Excel then find on the ribbon the 'Copy' icon, click on small triangle on the right and choose 'Copy as Picture'. Then you can select several options regarding details: as on screen or as printed, and picture or bitmap. The picture format can be easily scaled after pasting it to Word or Outlook, while keeping original formatting. Try experimenting.

just to share my methode.

I will copy from excel and paste into Word.

then only I copy the whole thing again and paste it into my Outlook.

hope this help.