You are allowed to work on campus if you are pursuing full time studies and are in possession of a valid Study Permit. Otherwise, you will need permission from an immigration office to work while studying in Canada.  In certain situations, you may be able to work while you are studying. Working will help you earn extra money and gain Canadian work experience.Do not work without being authorized to do so. If you do, you may be asked to leave Canada.

Working on campus

You may work on campus at the institution where you study without a work permit if:
you are engaged in full-time studies at:
a public post-secondary institution;
a private post-secondary institution that operates under the same rules and regulations as a public institution, receives at least 50 percent of its financing for its overall operations from government grants (currently, only private college-level educational institutions in Quebec qualify); or
a Canadian private institution authorized by provincial statute to confer degrees.
you have a valid study permit.

Working off campus

The Off-Campus Work Permit Program allows foreign students at publicly-funded post-secondary educational institutions to work off campus while completing their studies.

Publicly-funded post-secondary educational institutions are:

public post-secondary institutions that have signed an off-campus work agreement with their provincial or territorial government; or
private post-secondary institutions that operate under the same rules and regulations as public institutions, receive at least 50 percent of their financing for their overall operations from government grants, and have signed an off campus work agreement with their provincial or territorial government (currently, only private college-level educational institutions in Quebec qualify).

How do I participate?
To work off-campus, you have to apply for a work permit. Do not begin to work off campus until you have received your work permit. The work permit authorizes you to work up to 20 hours per week during regular academic sessions, and full time during scheduled breaks (e.g., winter or summer holidays and spring break).

To be eligible for an off-campus work permit, you will have to:
have a valid study permit;
be studying at a participating institution (see list above);
have been a full-time student for at least six of the twelve months preceding your application for a work permit;
be in satisfactory academic standing;
sign a form authorizing the institution, the province and CIC to share your personal information (in order to confirm that you are continuing to study full time and that you are in satisfactory academic standing);
complete a work permit application (available on the CIC Web site); and
include with your work permit application an official receipt to show you have paid the application processing fee of $150.

Note: Six (6) months of full-time studies:
Enrolment and participation in ESL/FSL programs are not included in the calculation of the six months of full-time studies.
If your institution considers a student to have "full-time" status during the "work experience" portion of the program and the student continues to comply with the institution’s co-op rules, the student will be eligible for the work permit. Participation in the work experience portion of the program can be included in the calculation of the six months of full-time studies. More Continued..........

Working In Canada Part 2
How To Study In Canada