With the continuous development of wearable electronic devices, the demand for energy storage devices with characteristics such as “light”, “thin”, and “flexible” is becoming increasingly urgent in the market. Flexible supercapacitors have the characteristics of fast charging and discharging rate, high power density, long cycle life, and safety and environmental protection. They are a promising energy storage device and have attracted much attention. In this book, by studying the preparation and characterization of graphene based flexible electrode materials, we aim to develop high-performance graphene based flexible supercapacitors that meet practical application needs. This book introduces various preparation strategies, rich material characterization methods, and electrochemical performance testing methods for graphene films. Therefore, this book can be used as a reference book for materials science and energy chemistry majors in higher education institutions.