This paper presents a method to design a monolithic complete-light modulator (MCLM) that fully controls the amplitude, phase, and polarization of incident light. The MCLM is made of birefringent materials that provide different refractive indices to orthogonal eigen-polarizations, the ordinary $\mathrm{o}$ and extraordinary $\mathrm{e}$ states. We propose an optimization method to calculate the two relief depth distributions for the two eigen-polarizations. Also, a merging algorithm is proposed to combine the two relief depth distributions into one. The corresponding simulations were carried out in this work and the desired light distribution, including information on amplitude, phase, and four polarization states, was obtained when a laser beam passed through a 16-depth-level micro-structure whose feature size is 8 μm. The structure was fabricated by common photolithography. An experimental optical system was also set up to test the optical effects and performances of the MCLM. The experimental performance of the MCLM agrees with the simulation results, which verifies the validity of the algorithms we propose in this paper.