A novel kind of light-modulating thermal image system (LMTIS) based on micromachining technology is described. This system incorporates the function of thermal image conversion and image intensification together on the base of a light-modulating thermal image device, a monolithically fabricated chip using CMOS compatible surface micromachining techniques. This system has a series of potential advantages: high sensitivity and definition, low volume and power expenditure as well as short response time and room temperature operating ability. The design and modeling of the device are presented. Theoretical calculations on the sensitivity, minimum detectable power, and response time are carried out by using a simplified cautilever beam theory, and the design is optimized for the sake of high sensitivity and low minimum detectable power. Finite element method (FEM) simulation using ANSYS 5.4 program demonstrates the theoretical calculations preliminarily, as a result, sensitivity of 0.03 m/W and response time of 6 ms are obtained.