A flexible conductive diaphragm comprises at least one conductive film, and the conductive film comprises a flexible support layer (1), a flexible sensitive layer (2) overlapped on the flexible support layer (1), a flexible conductive layer (3) overlapped on the flexible sensitive layer (2), and an electrode (4) electrically connected with the flexible conductive layer (3). A method for preparing the flexible conductive diaphragm and a flexible vibration sensor based on the flexible conductive diaphragm are provided. With the combination of the techniques such as the flexible material, the nano-material and the arrayed micro-structure, the flexible vibration sensor has the characteristics of high sensitivity, low preparation cost, light weight, small thickness, small size, and being foldable and flexible, and can be applied in wearable or adherable electronic devices.