Diabetes mellitus is a chronic disease with high prevalence around the world, which is imposing heaven burden to its society. Poor health literacy creates barriers to chronic disease care. Understanding the degree of health literacy and diabetes knowledge is a key factor to control and reduce complication of disease. Although there are a few health literacy tools available, but they are not applicable to the general Mandarin-speaking population due to the different culture and health promotion materials. Therefore, this study is aimed to develop a diabetic-specific health literacy instrument for Mandarin speaking population and to explore the health literacy of DM population in Taiwan.