In order to improve the neutron chopper design,the structural models of a single-chop-disk and an opposite rotate double-chop-disk were established. According to corresponding physical parameters, the neutron pulses formed by the single-chop-disk and the double-chop-disk were simulated by internationally popular Mcstas software respectively,and the influence curves of physical parameters on the pulses from the chop-chop- disks were obtained. Then,advantages and disadvantages of the neutron pulses generated by the single-chop-disk and the double disk were discussed. The discussion also refered to the influence of objective physical factors on the errors of neutron pulses generated by the single-chop-disk and the double-chop-disk.Considering the practical application,it suggests that the second cut width of the window in the double-chop-disk should be less than 34 mm in specific physical parameters. The results can provide the reference and theoretical support for optimizing design and manufacturing of choppers.