加拿大升學問題,,,

Yes, it's completely possible. However, HK universities have limited openings for overseas applicants.

去canada,,,讀grade12...讀完之後可以返HK讀大學ma?
Canada grade 12 + OSSD in Canada or GCE or other

CUHK non jupas Requirements
http://www2.cuhk.edu.hk/oafa/non_jupas.php?page=1§ion=Entrance%20Requirements
Applicants shall be eligible to apply for admission if they:
1) have obtained in one sitting of the GCE Advanced Level Examination pass grades in no less than three subjects (Applicants with pass grades in 2 GCE Advanced Level and 2 Advanced Subsidiary Level subjects may also apply); OR
2).. OR
3) ... (e.g. High School Diploma plus SAT in USA , HSC/TER in Australia, OSSD in Canada , etc.); OR

嶺南大學
http://www.ln.edu.hk/admissions/da/intl/f_admission.html
Non-local students should have attained at a recognised post-secondary institution outside Hong Kong a qualification equivalent to the normal entrance qualifications of the University, such as satisfactory completion of the 1st year of a 4 year undergraduate curriculum.

qualification equivalent to the normal entrance qualifications
http://www.ln.edu.hk/admissions/da/intl/download/admission_requirement.pdf

http://www.mcdonaldacademy.com/chinese/secondaryschool.php
安大略省高中畢業證書的要求：
學生需要達到以下條件方可畢業，並獲得安省高中畢業證書(OSSD)：
‧成功修完18個必修學分
‧成功修完12個選修學分
‧完成40小時社區義務服務
‧通過安省10年級英文能力測試
必修學分課程（18科/18個學分）
‧4科英文課程（9, 10, 11, 12年級各一科）
‧1科法文課程
‧3科數學課程
‧2科科學課程
‧1科加拿大歷史
‧1科加拿大地理
‧1科藝術類課程（美術或音樂）
‧1科體育課程
‧0.5科公民教育課
‧0.5科職業預備培訓課
另加:
‧1科英文，或第三語言，或社會學，或人文學，或加拿大和世界地理研究課程
‧1科體育，或藝術，或商業課程
‧1科科學（11/12年級）或科技教育（9-12年級）課程