A new method for analyzing the coupling degree of stressedlap driving forces based on the gray correlation analysis theory is proposed. One of the surface shape displacement vectors corresponding to stressedlap driving forces is taken as the primary sequence, and the others as the secondary sequences. The sequences are pretreated by using initial value processing, and the graycorrelationcoefficients (GCC) of subsequences are calculated. The graycorrelationdegree (GCD) can therefore be obtained using the GCCs of the subsequences. According to the concept of GCD, the GCD is explained as the coupling degree of secondary sequence to the primary sequence to achieve the quantitative calculation of coupling effect between the motors placed on a stressedlap. The proposed method provides a useful tool to make deep analysis and reasonable control strategies for stressedlap control systems. A case study on the coupling degree of an activelap with diameter 420 mm, 12 drivers, and 60 micromovement sensors shows that simulating results coincide with the actual situation, which means the proposed method can accurately describe the coupling degree between various drivers of a stressedlap.