教育統籌委員會(教統會)在2000年公布《香港教育制度改革建議》報告書中，提出了三年高中學制的構思，閱後成立工作小組，就實施新制的可行性、具體措施、過渡安排及推行時間表進行研究。2004年10月，教統局提出「三三四」改革方案，並隨即向公眾諮詢。新高中學制及課程改革，希望讓所有學生能修讀中六，並幫助學生建立更廣闊的視野和穩固的知識基礎，以為終身學習作準備。在考核方面，改革建議以一個新的「香港中學文憑」試取代現有的中五會考和中七高考，以減輕學生和教師的壓力及增加學習空間和時間。此外，改革亦建議加入校本評估，以更全面地評估學生的能力。數學科的有關課程改革構思，亦早於2003年底開展，課程發展處(CDI)及香港考試及評核局(HKEAA)，於當年十二月組織了高中課程發展委員會(CDG-HKEAA Committee on Mathematics Education (Senior Secondary))，去肩負這個重要的歷史任務。該委員會於2005年5月，發佈《新高中課程及評估架構建議：數學科第二次諮詢稿》，當中有關校本評估部份，可說是最具爭議性的。本文首先從理論和實踐角度出發，去探討數學科校本評估的可行模式、架構、方法和工具，從而討論校本評估於數學教育的價值，再深入探討和分析香港的數學校本評估政策和推行，並思考其對前線教師，師資培訓者和課程發展參與者可能帶來的挑戰和衝擊。

In 2000, the Education Commission proposed the new three-year senior secondary system in its newly published Reform Proposals for the Education System in Hong Kong. Working groups were then set up to study and investigate the feasibility of this new system, to formulate concrete measures, to develop transitional arrangements and to formulate working schedules. In October 2004, the then Education and Manpower Bureau (EMB) published a consultation document on the proposed new academic structure commonly know as "334". The new senior secondary system and curriculum reform aims at enabling every student to attain all-round development with sound basic knowledge for lifelong learning in future. In relation to the reform of assessment and examination system, a new Hong Kong Diploma of Secondary Education (HKDSE) was proposed to replace the existing HKCEE and HKALE at the end of S5 and S7 respectively, in order to create space for and reduce pressure on both students and teachers. Furthermore, in order to have a more comprehensive assessment of students' performance, school-based assessment was proposed to be a component of this new public examination. In response to such initiatives, mathematics curriculum reform had been formulated as early as 2003. Curriculum Development Institute (CDI) and Hong Kong Examinations and Assessment Authority (HKEAA) worked together closely to form the CDC-HKEAA Committee on Mathematics Education (Senior Secondary) in December of the same year to take up this important historical task of mathematics curriculum reform. In May 2005, the Committee published the Proposed New Senior Secondary Curriculum and Assessment Framework: Second Consultation Document of Mathematics. Since then, the suggestions on the development of school-based assessment have always been one of the most controversial issues. This paper will first examine, from both theoretical and practical views, the possible approaches, frameworks, methods and instruments for the development of mathematics school-based assessment. General values of school-based assessment in contemporary mathematics education will then be discussed. Second, the policy design and implementation of the Hong Kong mathematics school-based assessment will be investigated and analyzed. Finally, its possible challenges and impacts on frontline-teachers, teacher-educators and curriculum developers will be reflected on.