An apparatus capable of adjusting tensioning strength for use in a curtain driver, comprising a main drive unit (1) and adjustment suspensions (2), the adjustment suspensions (2) being symmetrically mounted on two sides of the main drive unit (1), and the adjustment suspensions (2) being connected to the main drive unit (1) in a snap-fit manner. Each adjustment suspension (2) comprises a face shell (21) and a bottom cover (22) which are fixedly installed together, a position-locking base (25) being disposed between the face shell (21) and the bottom cover (22) so as to be movable in the up-down direction, limiting blocking pieces (217) and limiting pieces (255) for limiting sliding distance being correspondingly disposed on the face shell (21) and on the position-locking base (25), a position-locking sliding block (24) being movably disposed within the position-locking base (25), a hook (241) being fixedly disposed on the position-locking sliding block (24), the position-locking sliding block (24) also being fixedly connected to a slingshot plate (23), the slingshot plate (23) being slidably connected to the bottom cover (22), and a spring (26) being disposed between the face shell (21) and the position-locking base (25). The structure is simpler, easier to adjust, replaces adjustment by buttons, prevents adjustment failure caused by the pulling force of a curtain hook, and has more uniform elastic force, a longer service life, and fewer traction structures, saving button traction force.