In response to the recent school creativity reforms in Asian places, this paper studied three different approaches of integrating creative thinking training into regular science lessons. They include developing creative thinking through science process, science content and science scenario. Three teacher case studies were conducted to examine the potentials and obstacles of implementing these approaches in classroom of Hong Kong. This study found that all the approaches were useful in developing student creative thinking, yet teachers experienced different tensions and dilemmas in different approaches. This paper suggests that the science content approach may be more readily accepted by teachers and students in an educational system which is dominated by knowledge content and examinations. However, with the limited skills and experience in creativity, teachers and students may feel that the science process and science scenario approach are easier to start with, as they are less constrained by the rigid content in the syllabus. Among various hindering factors, the most crucial one was found to be the original heavy knowledge-content, which in fact is a common characteristic of secondary science curriculum in many Asian places. In our future research and educational reforms, the dilemma between creative thinking and content learning needs to be seriously considered and solved at both individual and system levels.