The refraction lithography lens has many units, which are easily deformed by gravity forces. However, the lens mount flexure design can relieve lens surface gravity deformation. The lithography lens generically has more than 10 lens units, so with each unit, the gravity deformation sum will create large aberrations in the system. The flexure number can generate a relative aberration, such as trefoil, tetrafoil, and high-order aberrations. In addition, the lens flexure orientation can compensate for non-symmetric to symmetric aberrations from effects of gravity deformation. Thus, symmetric aberrations must resist magnitude in one or two lens units through the measurement data. This study attempts to calculate and predict lens gravity deformation; the results can assist with optical design and reoptimize system performance, as well as reduce the rework risk by measurement data.