Abstract: The paper presents a measurement system which uses reformed atomic force microscope(AFM) as sensor, combined with precision rotating air bearing and 3 D micro positioning device. The precision measurement on shape error of the inertial confinement fusion(ICF) target's circle is carried out. The results show that this method can be applied in the technology of ICF target making and can provide the accurate data of target's surface profile for experiments of ICF target practice.