Abstract: Precise instruments and devices used on aircrafts should follow low frequency motion as aircraft taking off and on normal fying; on the other hand, they should also isolate the high frequency motion caused by spurting fuel, etc. This paper studied a novel isolating method-electromagnet and permanent magnet suspension isolation. After establishing the physical and mathematicn models concerning horizontal and vertical translation freedom degree, the paper proposed a pole-placing method to design the control system. By computer simulation, it is indicated that the control system could meet the task well.