A two dimensional electrostatic particle simulation was done to study the extraction of positive (negative) ions from a volume plasma source. The simulation model is a rectangular system which consists of an extraction grid (left wall), a plasma grid, and a grounded wall (right wall). Upper and lower boundaries are connected by the periodic boundary condition. Full dynamics of charged particles are followed. Positive (negative) ions are extracted from the plasma region through a slit in the plasma grid to the extraction grid. Electrons are reflected by the magnetic filter and confined in the region to the right of the magnetic filter. Simulation results are compared with the Child–Langumuir law where the extracted ion current is proportional to the three‐halves power of the potential of the extraction grid. In the case of the positive ion extraction, simulation results agree quite well with the Child–Langumuir law. Whereas, in the case of the negative ion extraction, simulation results agree with the law only for the lower value of extraction grid potential.