Drink driving in Canada is a really serious matter.
Criminal inadmissibilityIf you have committed or been convicted of a criminal offence, you may not be allowed to enter Canada.
Criminal offences include both minor and serious offences, such as theft, assault, manslaughter, dangerous driving and driving while under the influence of drugs or alcohol.
For a complete list of criminal offences in Canada, consult the Canadian Criminal Code.
Also read
http://www.canadavisa.com/immigration-problem-criminal-inadmissibility.html