Patentability is one of the most controversial issues in patent law and deserves much discussion, research and reflection. Patent law specifies the general field of subject matter that can be patented and the conditions under which a patent may be granted. In the development of patent law, the scope of patentable subject matter should be reviewed regularly to correspond with the advancement of new technologies which are bound to continually test the boundaries of patentability. For example, the Supreme Court of the United States has recently ruled that naturally occurring genes are not patentable, but cDNA is patentable as it is a man-made copy of the genetic messenger in cells. Although patent protection is territorial in nature, technology development, which generally has no boundary, will affect all human beings around the world, and it may cause some classical problems and new challenges with respect to the patentability of new technologies. The aim of this research is to re-examine whether diversities in the area of patenting biotechnology are problematic and, based on the discussion, further explore how to harmonize the patentability of biotechnology at the international level. By adopting the methodology of Martin Boodman, the first part of this dissertation reviews the literature of patentable subject matter and the new challenges triggered by the development of modern biotechnology. As to the theory of harmonization, three features, including the preservation of diversity, the formation of a harmonized whole and the requirement of consonance, will be introduced and then applied to the analysis in this first part. The second part starts with a review of the global diversities of patenting biotechnology and compares the TRIPs minimum standards and the different approaches taken by the US, the EPO countries and China. The findings show that those diversities have brought some disharmony problems to patentability in respect of biotechnology at an international level. With the aim of addressing these problems, it is concluded that a more harmonized framework between the Convention on Biological Diversity (CBD) and the TRIPs Agreement would be more meaningful with respect to international harmonization of patentability from a problem-solving perspective in the era of modern biotechnology. It is further observed that international substantive harmonization of the patentability of biotechnology would mostly depend on the application of the key issues of appropriability and access. Finally, this dissertation analyzes the new domestic and international situations faced by China, and highlights the necessity and significance for China to fight for better appropriate and accessible patentability for biotechnology under the international patent system.