Abstract: To address the issue of inconsistent imaging coordinate systems and carrier coordinate systems caused by the introduction of vibration isolation systems in optoelectronicequipment, a relative attitude measurement method based on eddy current displacement sensors is proposed. First, the mapping relationship between the measured point positions on the tested surface and the three-dimension relative attitude is derived using the principle of coordinate rotation transformation, and the relative attitude solution equation of the vibration isolation system is established. Then, the conditions required for eddy current displacement sensors to accurately solve the relative attitude are analyzed. The relative attitude determination accuracy under current application conditions is analyzed using the Monte Carlo method, resulting in a precision of ±0.003 degrees. Finally, a relative attitude measurement experiment based on eddy current sensors is designed, where 8 high-precision eddy current sensors and 2 theodolites are used to verify the effectiveness and accuracy of the proposed relative attitude solution method. The results show that the maximum error between the relative attitude solution values obtained via the eddy current displacement sensors and the true values measured by the theodolite is 0.008 degrees. The relative attitude measurement method proposed in this paper can effectively solve the problem of unifying the imaging coordinate system and the carrier coordinate system caused by the vibration isolation system, and has application value in optoelectronic vibration isolation systems.