As one of the key components of an optical system, the processing quality of the lens greatly affects the performance of the optical system. The variation of the lens' center thickness has the most significant impact on the overall imaging quality of the optical system. The existing non-contact and contact measurement equipment has some shortcomings. Therefore, this paper proposes a diameter adaptive method for measuring the center thickness of a lens. Based on this method, a set of lens center thickness measurement device was designed and built. The measurement accuracy comparison and the repeatability measurement test are carried out. The results show that the error of the measurement device studied in this paper is comparable to the error of the measurement device used in the production line, which meets the detection requirements of optical lenses. The device has the advantages of simple and reliable structure, convenient operation, high measurement accuracy, and saving the production cost of optical lenses, and has been used in production lines.