We propose a self-adaption focal length adjustment method of a compound and human hybrid eye with a non-uniform microlens array model (NUMLA) to reduce defocus aberration by using the liquid lens. The models are deduced and verified through simulations. The method can self-adaptively adjust the focal length according to object distance and image distance. The results show that (1) the RMS spot radii of the traditional uniform microlens array at different rings are 21 μm, 187 μm, 304 μm, 526 μm, and 803 μm. However, those of the NUMLA are 21 μm, 47 μm, 98 μm, 178 μm, and 287 μm, which indicates that the NUMLA can reduce the defocus aberration. (2) When the object distance and the image distance vary, the defocus aberration can be significantly reduced through the adjustment of the focal length, which validates the effectiveness of the proposed method. (3) The volumes of the liquid lens in the cavity at the peripheral rings are larger than that at the central rings. The results are beneficial for providing a simple solution to reduce the defocus aberration of the compound and human hybrid eye.