Length-adjustable shock absorber

The utility model relates to a length-adjustable shock absorber, which belongs to the field of shock absorbers and comprises a support column, an oil storage barrel, a sliding column and an extension rod. The oil storage barrel and the supporting column are arranged side by side. The oil storage barrel communicates with the supporting column; the sliding column is slidably arranged on the supporting column. Pistons are arranged at the lower ends of the sliding columns; the piston is embedded into the supporting column and is in sliding connection with the supporting column; a reset spring used for driving the sliding column to move is arranged on the supporting column. The extension rod is slidably connected with the sliding column. The lower end of the extension rod is embedded into the sliding column; the sliding column is provided with a lifting mechanism used for driving the extension rod to move in the vertical direction. And a driving mechanism for driving the lifting mechanism to rotate is arranged on