In order to meet the requirement of an optical system design on the spherical surface via the thin-film elastic deformation of liquid lens, a numerical optimization method is implemented on the elastomeric supporting region of liquid lens using the solid isotropic material with penalization type topology optimization model and moving asymptotes constrained optimization algorithm. The topological configuration meeting the convergence conditions is obtained. According to the topology optimization results, the shape optimization is further implemented for key structural dimensions. And a manufactureable elastic thin-film liquid lens is designed according to micromachining technology. Surface error of optical thin-film is analyzed based on the deformation of thin-film. The peak valley (PV) and root mean square (RMS) values about surface error are calculated on the different diameters. The numerical results show that the optical surface error PV values of the optimized structure are 5.7%, 11.9% and 2.5% of the initial structure, respectively, and the RMS values are 11.2%, 21.9% and 45.4% of the initial structure, respectively, at diameters of 100%, 95% and 90% of thin-film and the height of chord of 0.5 mm. The deformation of the optical thin film is fitted with 36 Zernike polynomials. Fitting results show that the 4th, 9th, 16th, 25th Zernike coefficients are also obviously reduced.