Disclosed are a flexible substrate and a method for manufacturing the same, and a flexible electronic device. The flexible substrate includes: a flexible base; a plurality of electronic components disposed on the flexible base, a first gap being formed between each two adjacent electronic components of the plurality of electronic components; and a plurality of metal lines, wherein at least one end of each of the metal lines is connected to the corresponding electronic component, at least a portion of the plurality of metal lines are disposed in the first gap, and a length of each metal line disposed in the first gap is greater than a width of the first gap in an extension direction of the metal line; wherein a first filling layer is disposed in the first gap to wrap the metal line disposed in the first gap.