The invention discloses an office chair which comprises a seat part and a support part used for supporting the seat part, wherein the support part at least comprises connecting mounting rods bent intoangles and chair leg components mounted through the connecting mounting rods; the seat part at least comprises a seat plate and long slots formed in the back of the seat plate and used for embeddingthe connecting mounting rods; the slot width of the long slots is more than the diameter of the connecting mounting rods; a plurality of blocking components are fixedly arranged on slot walls of the long slots; the blocking components at least comprise mounting sheets fixedly mounted on the slot walls of the long slots, resisting sheets opposite to the mounting sheets and elastic connecting partsfor electrically connecting the mounting sheets with the resisting sheets; the blocking components are stuck between the slot walls of the long slots and the connecting mounting rods, so that the connecting mounting rods are fixedly embedded into the long slots. The office chair has the advantages of convenience in detaching and structure stability in repeated mounting and dismounting process.