The generation of high accuracy calibration force is one of the key factors for high precision measurement of micro thrust. With the advantages of noncontact, structure simplicity, control easiness and etc., electromagnetic force has become an effective method to generate calibration force in micro thrust measurement system. Aimed at the performance requirements of electromagnetic calibration force in micro thrust measurement, the effect of relative position changes between the magnet and the coil on the magnitude of the electromagnetic force is focused. The output characteristics of the electromagnetic force with vertical distance, radial deviation, relative angle changes are obtained by simulation: the electromagnetic force is symmetric along the central axis of the magnet and will become larger when the relative angle and the radial deviation are not zero; the electromagnetic force increases first and then decreases when axial distance increases. Based on the balance weighing method, a 3D adjustable electromagnetic force measurement device is designed and a zero adjustment method of axial distance, radial deviation and relative angle is proposed. Relatively complete mechanical properties are obtained by the piecewise fitting method, the problem of large relative error in small calibration force output is solved. The control relationship between the electromagnetic force and the current is obtained, and the relative position variation range is specified. The new concepts such as insensitive angle, insensitive radial deviation, insensitive axial distance section and etc. are put forward, which provide specific parameters for performance characterization of the electromagnetic force generating device.