Blood glucose (BG) concentration of the human body serves as an important index for diagnosis of diabetes, and its detection methods need to be more e±cient due to high mortality rates for diabetes. Typical household BG meters are invasive products based on electrochemistry and rely on finger pricks to procure blood, which might result in skin damage and bacterial infections. Moreover, such BG meters can only detect the BG concentration at a certain time while ignoring the BG level at other times. Recently, to achieve microinvasive, noninvasive and continuous glucose monitoring (CGM) by detecting body fluid, such as sweat or tears, the research direction has been gradually developing toward wearable devices. This review discusses the glucose detection mechanism of various electrochemical and optical glucose sensors, and briefly analyzes their advantages and challenges. Additionally, wearable products based on various principles that have appeared on the market are also summarized. Furthermore, based on the analysis, this review proposes a design concept for future research directions.