Based on confocal imaging principle, the confocal line scanning imaging technique uses the one-dimensional scanning-line beam to illuminate the sample for increasing imaging speed. A confocal slit is used to filter the stray light from unfocused-level for improving imaging resolution and contrast ratio. Recently, the confocal line scanning imaging technology is becoming more and more popular in biomedical imaging because of its advantages such as high imaging speed, high imaging resolution, simple system structure, and so on. We introduce the basic principle of confocal line scanning imaging, and list main parameters of the imaging system and their influencing factors. Then the application in biomedical imaging especially in fundus imaging and biological tissue cell observation is illustrated. Advantages, disadvantages, and application prospect of the technique are finally summarized.