The utility model provides an ion implanter with an extraction slit, aiming to solve the problem that a present ion implanter has the disadvantages of complex processes and high equipment costs for ion implantation. The ion implanter comprises an iron source system provided with antennas and a discharge chamber and an extraction system provided with an extraction slit. The antennas are arranged outside the top of the discharge chamber and are arranged in a length direction of the extraction slit. The iron source system is driven by an RF power supply. The ion implanter of the utility model simplifies a structure of an ion implanter, can omit an expensive plastic magnet and uniformity adjusting unit, simplifies ion implantation processes and reduces ion implantation costs.