Abstract: The emittance is an important parameter of the ion source, reflecting the quality of the beam. The emittance is also the starting point for the design of accelerator and beam line. The CYCIAE-100 cyclotron uses an 18 mA high intensity ion source to produce H^- ion beam. One type of emittance scanner for high intensity H^- ion beam was designed in order to get the precise measure of the ion source emittance. The working principle, mechanical design and experiment results were introduced, and the emittance of H^- ion source was gotten. The measurement results can be used for the design of the CYCIAE-100 cyclotron.