A circular stapler and a staple component thereof. The staple component comprises a staple barrel component and an anvil component. The anvil component comprises an anvil ring and an anvil shaft that are fixedly connected to each other. The anvil shaft slides along the longitudinal direction in the expansion-stopping tube. The staple barrel component comprises a staple barrel, a staple push piece arranged within the staple barrel, and a staple cartridge fixed at the distal end of the staple barrel. The distal end of staple barrel component is a staple cartridge surface. The staple barrel comprises a tubular housing, the expansion-stopping tube arranged within the housing, and a stiffener. The housing is provided with a first cavity for accommodating tissues to-be-incised. The proximal end of the housing is for use in connecting to a main body of the circular stapler. The distal end of the housing is for use in mounting the staple cartridge. At least one opening is provided on the sidewall of the housing of the staple barrel. The opening is in communication with the first cavity. The distance running from the distal end of the expansion-stopping tube to the staple cartridge surface is greater than the distance running from the distal end of the opening to the staple cartridge surface. At least a portion of the first cavity is exposed via the opening. This not only provides a large window during surgeries, but also allows during surgeries for convenient pulling-in of tissues and accommodation of an increased amount of tissues for incision.
