Endoscope, a commonly used multi-disciplinary fusion instrument, is important in screening, clinical diagnosis, intraoperative detection, and prognosis assessment of major malignant diseases. Compared with other optical analysis techniques, Multispectral Imaging (MSI) provides both imaging and spectral information and has more advantages in clinical endoscopy optical detection. We developed a fast multi-spectral endoscopy imaging system with Xenon light source, hard tube endoscope, and imaging CCD. We evaluated its imaging performance using living rat testicular tissue as the study object. The system uses six 3-channel narrow-band filters as spectral splitting devices, which can simultaneously achieve three 15 nm narrow-band lighting (~ 15 nm bandwidth) in blue, green, and red wavelengths. After the illumination light is transmitted to the hard tube endoscope through the optical waveguide fiber, the CCD collects the narrowband image and video information corresponding to each filter in real-time (24 MSI data sets per second). The Adaptive Histogram Equalization (AHE) algorithm and CIELab color space model improve the contrast of the obtained multi-spectral images. Combined with the tissue optical transmission model, based on reconstructing tissue multispectral image information, physiological characteristics of living biological tissues (blood content, oxygenation index, scatterer size distribution images, etc.) are further visualized. The experimental results showed that processing MSI images significantly enhanced the visibility of surface tissue blood vessels, subcutaneous microvessels, and other tissue structures and was more conducive to observing tissue texture and capillary distribution. The reconstructed physiological features visualized the differences in blood volume distribution between different tissue parts. By analyzing tissue reflectance spectral characteristics, differences in blood content within tissues can be further quantitatively assessed. The MSI-based endoscopy technology and its detection system in this paper can further quantitatively analyze the biochemical composition information inside tissues on the premise of visually describing the morphological characteristics of tissues without labels, which is helpful to explore and form a new endoscopy optical detection technology that meets the requirements of early detection of clinical cancer.