It is extremely important to measuring accurately beam emittance on modulating accelerator beam and evaluating accelerator performance.The paper introduces the ion beam emittance measurement system with the three gradient method on the base of already existed devices of Heavy Ion Research Facility in Lanzhou（HIRFL）.It also discusses measure principle

method and some problems to which we pay attention in measurement system. Methods of caculating and processing data are emphasized. Moreover

a suit of software system is designed to realize measurement and display of the beam parameters.The System has good reliability

visual display and accurate measure.