Hi Rimi
Your husband enters as a visitor first and then attaches a copy of your student permit to his application for a work permit. I found this for you: -
Work permits for spouses
Spouses or common-law partners of international students are allowed to apply for a work permit to work on or off campus. Your spouse should enter Canada as a visitor and then can apply for a work permit once he or she is here. Application forms are available on the Citizenship and Immigration Canada website.
When your spouse applies for the work permit, he or she will need to provide a legal marriage certificate or proof of common-law status (see the application form for details) along with a copy of your study permit.
I'm not positive but I think you follow the guidelines and forms found on this page of the CIC website
http://www.cic.gc.ca/english/information/applications/extend-worker.asp.
Hope that helps.