As a solution to the problems of image registration difficulty，small field of view angle，and high costs associated with traditional dual-spectrum imaging systems，a dual-spectrum imaging system based on unit scanning was developed in this study. This system separated infrared and visible light by passing it through a beam splitter，in which the infrared light was converged by an infrared focusing lens to an infrared unit sensor，and the visible light was converged by an ordinary optical lens to a visible light sensor. Dual-spectrum imaging was achieved using the equal-time scanning sampling method. To improve temperature measurement accuracy，the system compensated for the variations in imaging distance and angle and used the bilinear interpolation image mapping method to make the resolutions of the collected infrared and visible light images consistent. The experimental results showed that the dual-spectrum imaging system based on unit scanning has a wide field of view， can map infrared images to visible light images without image registration，and has a low cost.