From "How to Produce Neutrons" point of view, the design of moderator used for pulsed neutron source is described for neutron scattering experiments. The pulse characteristics of high peak intensity, narrow pulse width and short tail, are three essential elements for short-pulsed neutron beam, which is produced by slowing down process of fast neutrons in a moderator. The high peak intensity and the narrow width are in a relationship of trade-off. We developed three kinds of moderators, which dedicated to peak intensity or narrow width or short tail, for MW class short-pulsed neutron source. Each neutronic performance of moderator is described.