Frame shock damper for bike

The utility model relates to a frame shock damper for a bike, comprising a frame body which is arranged on the lower section of a seat pad vertical tube, is provided with two convex ears and is pivoted with a joint block through a pin body, wherein, the joint block is connected with a back lower fork, both ends of the joint block are provided with pyramidal concave grooves, and two sheath bodies with pyramidal ends together with a thrust bearing are sheathed in the joint block; the pin body passes through the two sheath bodies so that the joint block can be pivoted and rotated, and the sheath bodies can bear the force generated in vibration through the match of the pyramidal surface, so the pin body does not have to bear oversized load.