The Greencard scheme

It is possible to be granted a residence permit for the purpose of seeking work and working in Denmark. A residence and work permit under the Greencard scheme is issued on the basis of an individual evaluation based on a point system. 

If you are granted a residence permit under the Greencard scheme, you do not need to obtain a separate work permit. A residence permit under the Greencard scheme gives you the right to carry out paid or unpaid work. However, a residence permit under the Greencard scheme does not give you the right to work as a self-employed person (run your own business).

 You can find more information regarding this  from this link http://www.nyidanmark.dk/en-us/coming_to_dk/work/greencard-scheme/