A flexible array substrate, a manufacturing method thereof and a display device are provided. The flexible array substrate includes: a first flexible substrate with a first surface; a thin film transistor on the first surface; and a light-shielding layer between the first flexible substrate and the thin film transistor. An orthographic projection of the light-shielding layer on the first flexible substrate covers an orthographic projection of a channel region of the thin film transistor on the first flexible substrate.