A tunable reflecting micro-optoelectromechanical systems (MOEMS) micromirror is designed for measuring the actual temperature and color of an object based on comparison of two wavelength response windows, 3-5 and 8-12 µm. The MOEMS micromirror with switching between two positions by an applied electrostatic voltage provides a response to two wavelength windows by tuning the optical resonant cavity. Three different structural models of the tunable micromirror, which are made up of single Al layer with type I legs, single Al layer with type L legs, and double Al/Si3N4 layers with type I legs, are designed and simulated accurately using ANSYS tools on a 35-µm pixel-pitch array. On the basis of the comparsion, the third model, made up of double Al/Si3N4 layers with type I legs, is chosen. With different distances between the MOEMS micromirror and the bottom electrode, the total capacitance of the tunable micromirror is gained based on electromagnetic analysis and theoretical equation. The pull-in voltage is calculated as 8.21 V by electrostatic-mechanical coupling analysis, and the maximum stress is 368.744 MPa, which is less than the yield strength of Si3N4 thin film. But if the voltage is increased to ~9.73 V, the micromirror will touch the bottom electrode by pull-in behavior.