A developing cartridge (500, 600) detachably installed into a printer, wherein a cover of the printer is provided with a plurality of chip contact heads, each of the chip contact heads comprises an end surface and a side surface, the developing cartridge (500, 600) comprising: a cartridge body, and a chip (45, 75) and a plurality of conductive connecting pieces provided on the cartridge body, wherein the cartridge body comprises an upper surface that is facing up and a back surface that is facing down when the developing cartridge (500, 600) is installed and inserted into the printer, characterized in that one end of each conductive connecting piece is connected to a chip terminal (451, 751), and when the developing cartridge (500, 600) is installed and inserted into the printer and the cover is closed, the other end of the conductive connecting piece comes into contact with the side surface of a corresponding chip contact head on the cover of the printer, so that the side surfaces of the chip contact heads on the cover of the printer press the developing cartridge (500, 600) upward or downward when coming into contact with the conductive connecting pieces, and a read end of the upper surface of the cartridge body is provided with a stepped surface (61, 502) with the read end close to the plurality of chip contact heads on the cover, and the plurality of conductive connecting pieces are provided on the stepped surface (61, 502), wherein the developing cartridge (500, 600) further comprises a chip holder (63, 73), wherein the chip holder (63, 73) is provided on the back surface of the cartridge body, and the chip (45, 75) is installed and fixed in the chip holder (63, 73), wherein each of the conductive connecting pieces comprises: a front-end limit hole, an elastic sheet stamped in the middle and a back-end arch-shaped contact surface; at a position corresponding to the chip holder, the upper stepped surface of the cartridge body is provided with a press bar, and limit buckles arranged in a row, a through hole which runs through the upper stepped surface and the back surface of the cartridge body is provided, the press bar locates at front end of each of the conductive connecting pieces, a plurality of limit posts matching the number of the chip terminals are provided at the back of the press bar, the front end of each of the conductive connecting pieces is inserted into the back of the press bar, the limit holes of the conductive connecting pieces are pressed and socketed to the limit posts of the press bar one by one, the limit posts and the conductive connecting pieces are in a hot-melt fixed connection, the elastic sheets pass through the through holes to stand against the chip terminals so as to achieve electrical connections between and the conductive connecting pieces and the chip. a cartridge body, and a chip (45, 75) and a plurality of conductive connecting pieces provided on the cartridge body, wherein the cartridge body comprises an upper surface that is facing up and a back surface that is facing down when the developing cartridge (500, 600) is installed and inserted into the printer, characterized in that one end of each conductive connecting piece is connected to a chip terminal (451, 751), and when the developing cartridge (500, 600) is installed and inserted into the printer and the cover is closed, the other end of the conductive connecting piece comes into contact with the side surface of a corresponding chip contact head on the cover of the printer, so that the side surfaces of the chip contact heads on the cover of the printer press the developing cartridge (500, 600) upward or downward when coming into contact with the conductive connecting pieces, and a read end of the upper surface of the cartridge body is provided with a stepped surface (61, 502) with the read end close to the plurality of chip contact heads on the cover, and the plurality of conductive connecting pieces are provided on the stepped surface (61, 502), wherein the developing cartridge (500, 600) further comprises a chip holder (63, 73), wherein the chip holder (63, 73) is provided on the back surface of the cartridge body, and the chip (45, 75) is installed and fixed in the chip holder (63, 73), wherein each of the conductive connecting pieces comprises: a front-end limit hole, an elastic sheet stamped in the middle and a back-end arch-shaped contact surface; at a position corresponding to the chip holder, the upper stepped surface of the cartridge body is provided with a press bar, and limit buckles arranged in a row, a through hole which runs through the upper stepped surface and the back surface of the cartridge body is provided, the press bar locates at front end of each of the conductive connecting pieces, a plurality of limit posts matching the number of the chip terminals are provided at the back of the press bar, the front end of each of the conductive connecting pieces is inserted into the back of the press bar, the limit holes of the conductive connecting pieces are pressed and socketed to the limit posts of the press bar one by one, the limit posts and the conductive connecting pieces are in a hot-melt fixed connection, the elastic sheets pass through the through holes to stand against the chip terminals so as to achieve electrical connections between and the conductive connecting pieces and the chip.