With the development of nanotechnology, it has been accessible to display colors by artificial micro/nano-structure, and then the study of structure coloring has become a hot subject, opening a new space for inkless printing. In this paper, a dynamic color modulation method based on tunable micro/nano-structure array is proposed. To tune colors on the same device, a periodic micro/nano-structure array is designed with functional material inside, which could alter the height difference between up and bottom surface precisely by applying an external voltage. It is modeled, and simulated by the Finite Difference Time Domain (FDTD) method in this work. In simulations, perpendicular incident linearly polarized light source is applied, and parameters of surface height difference and period are swept. Series reflective spectra of the devices are obtained, and their corresponding colors are calculated and marked on the CIE 1931 chromaticity diagram. Simulation results demonstrate that when the period is in the range of 100-300 nm, full-color modulation could be realized by varying the height of functional material film via applied voltage, and the peak intensities of reflective spectra are at about 60%, having high energy efficiency. This method is innovative and provides a theoretical basis for the dynamic color modulation micro/nano device, which is quite promising in fields like inkless printing and display technology.