The invention discloses a liftable self-adaptive
pulley device which comprises a shell, a
pulley body, a spring leaf, a rotary sheet, a
magnet, a supporting frame, a buffer wheel, a buffer sheet, connection rods, a top plate, a rotary frame, a rotary fixed sheet, a lifting screw rod, a buffer bulge, bearings, a
pulley body center shaft and connection screw rods. In the use process, the liftable self-adaptive pulley device provided by the invention is good in muting effect, stable in running and smooth in labor conservation, can realize automatic buffer and
speed reduction, can avoid noises caused by collision of sliding
doors, avoid persons nearby from being hurt by jamming when a sliding door mechanism is closed due to negligence or avoid the condition that the sliding door mechanism collides an object nearby to cause damage of the object, is high in safety degree in the use process and good in thickness and shape adaptability of a door body, can realize self-adaptive flexible regulation on the thickness of the door body during mounting, can realize easy and flexible up and down regulation of a height of the sliding door body and meets the lifting demand of a user under a specialcondition.