The present invention provides a developing cartridge, including a chip and conductive connecting pieces, provided on the developing cartridge, a cover of a printer is provided with chip contact heads, where one end of each of the conductive connecting pieces is connected to a chip terminal, and when the developing cartridge is inserted into the printer and the cover is closed, the other end of the conductive connecting piece contact with side surface of the chip contact head on the cover and squeezes the developing cartridge, preventing the developing cartridge from vibrating up and down during use.