The invention discloses a hydrogenated styrene-conjugated diene copolymer as well as a preparation method and application thereof in self-adhesive films. The hydrogenated styrene-conjugated diene copolymer has the following expression: S1-EB1-S2-EB2, wherein S1 and S2 are styrene blocks; EB1 is a hydrogenated butadiene block; and EB2 is a hydrogenated conjugated diene block. The hydrogenated styrene-conjugated diene copolymer has good processing properties and can be used for preparing the self-adhesive films together with other poly stylene polymers; and the prepared self-adhesive films are less affected by temperature, humidity and other external conditions, have good stability, have adhesive strength capable of being controlled within a wide range, and are suitable for application requirements of various materials.