The utility model relates to a shock absorber, including a store oil section of thick bamboo, piston rod assembly is connected to store oil section of thick bamboo one end, piston rod assembly passesthrough the oil blanket seat with store oil section of thick bamboo junction and seals, a store oil section of thick bamboo is equipped with rings respectively with piston rod assembly, be equipped with O type circle in the store oil section of thick bamboo, O type circle becomes store oil chamber and air storage chamber with store oil section of thick bamboo internal partitioning, O type circle outer joint has floating piston, floating piston is I -shapedly, both ends are equipped with first cavity and second cavity respectively about it, first cavity in -connection has the piston, O type circle is connected in the second cavity, piston rod assembly is including the piston rod, piston rod one end is connected with the piston assembly, the piston assembly is including being close to the check valve that first cavity one end set up, the beneficial effects of the utility model are that: contact between a floating piston and the store oil section of thick bamboo is the face contact, has improved the interior floating piston's of shock absorber life greatly, has prolonged shock absorber's life, and first sleeve pipe and second sheathed tube exist makes the motion of piston rod more level and smooth.