A new ion extraction system has been developed for use with the light ion source apparatus (LIISA) of the Accelerator Laboratory. The aim of the new extraction system is to have a more intense and better quality beam. For simulation of the beam behavior at the extraction region a computer codeIGUNehas been used. The simulation shows that a simple triode extraction would be efficient enough to extract total beam intensities of around 5 mA at an extraction voltage of 10–15 kV. At the same time, with the carefully designed plasma electrode, the emittance could be decreased significantly from the original design. The new extraction was installed in May 1997 and the results have been encouraging. The transport efficiency of the extracted beam to the first Faraday cup (at a distance of 1.2 m) was 100&percent; and the maximum proton current obtained was 2.0 mA. The maximum proton current in the cyclotron inflector is 1.0 mA, which is eight times larger than the previous record. ©1998 American Institute of Physics.