Flexible substrate structure and method of forming same, and flexible electronic device

Disclosed are a flexible substrate structure and a method of forming the same, and a flexible electronic device. The flexible substrate structure comprises a flexible underlayer (100); a planarization layer (110) located on the flexible underlayer (100), a surface thereof located away from one side of the flexible underlayer (100) being flat; and a barrier layer (120) located on the planarization layer (110), the barrier layer (120) being used to block the permeation of oxygen and water vapor. The flexible substrate structure can effectively block the permeation of oxygen and water vapor, thereby improving the reliability and service life of an electronic device formed thereon.