The invention discloses a pin shaft assembly which is provided with a pin shaft, a first stopping block, a second stopping block and a plate spring (4). The first stopping block and the second stopping block are arranged on the pin shaft (8) and spaced along the axial direction of the pin shaft, the plate spring (4) is provided with a substrate portion (41) and first and second bent board portions (43 and 45), the first and second bent board portions (43 and 45) are backwards bent from two ends of the substrate portion and extend along two opposite directions which are parallel to the substrate portion, a free end (13) of the first bent board portion (43) is upwarped along the direction of enlarging of a gap between the first bent board portion and the substrate portion, two ends of the substrate portion elastically abut against the first stopping block (10) and the second stopping block (11) respectively, a limiting protruding portion (12) is arranged on at least one stopping block of the first stopping block and the second stopping block, and the at least one stopping block of the first stopping block and the second stopping block faces the free end (13) of the first bent board portion (43). The invention further provides a rolling bar chain with the pin shaft assembly. When the pin shaft assembly is used as a connection part to connect a connected part, installation and disassembling of the connected part are convenient and fast.