The invention relates to an adjustable damper. The adjustable damper mainly comprises a shell, a piston bolt, a piston plate, a piston sealing ring, a piston, a connecting bolt, a T-shaped installingbase, a through cover outer sealing ring, a through cover, a through cover inner sealing ring, a through cover bolt and the like. The head of the piston is provided with a kidney-shaped hole for installation and a circulation gate hole set of damping media, the total cross sectional area of the circulation gate hole set is determined in cooperation with a baffle, and therefore adjustment of damping coefficients is achieved. The damper can be installed on many structure and equipment through an installing hole of the T-shaped installing base and an installing hole of the shell. The adjustable damper is simple in structure, reliable in work and high in economic benefit, and adjustment of the damping coefficients can be achieved according to the actual needs.