Spectral imaging integrates spectral analysis with digital imaging to capture spatial and spectral information, offering enhanced object analysis beyond traditional methods. It spans wavelengths from ultraviolet to infrared, utilizing technologies like light sources, detectors, and data algorithms. Key systems include grating-based, point-scanning, multispectral, and hyperspectral imaging, each with unique advantages in biomedicine, environmental monitoring, and material analysis. The chapter addresses the transformative role of spectral imaging in medical diagnostics, where it improves tumor detection, disease monitoring, and drug development via non-invasive, real-time monitoring. AI integration further boosts its application in traditional Chinese medicine and food quality control. Spectral imaging promises to revolutionize scientific research, medical diagnostics, and industrial applications in future.