Abstract: After fully assimilating control experts experience we developed a new intelligent integrator togather with itsmathematical model.Its frequency responses had been investigated and discussed by the harmonics lincarization method.Its phase lag is found to be only 27.6°.All high order harmonics are very small.And it is very resistant to disturbances.By using it we designed further an optimum system with very good control performances for both unit step input and unit ramp input.It must have good prospects in application.