Disclosed in the present invention is a single-sided flexible circuit board, comprising a bonding layer, circuits embedded in the bonding layer, a solder mask layer located at the upper side of the bonding layer, and a surface protection layer located at the lower side of the bonding layer; a plurality of hollow bonding pad regions are provided on the solder mask layer; the bonding pad regions are correspondingly provided directly above at least a part of the circuits; and the upper surfaces of the circuits directly below the bonding pad regions are provided with surface processing layers. According to the present invention, circuits in a single-sided flexible circuit board based on separable copper foils are embedded in a bonding layer, the width and the distances of the circuits are further reduced while high reliability is maintained, products are ultrathin in size, the bending performance and the assembling performance are good, reducing the risk of short circuit of a package on the client; and according to the present invention, a film preparation method for a single-sided flexible circuit board based on separable copper foils has low cost and high reliability, and is easy to implement and suitable for batch production.