Fiber-like structure is one of the basic structures found in biological tissues. The spatial orientations of fiber-like structures change with the initiation and progression of some diseases. In this study, we present a brief overview of quantitative orientation analysis methods for fiber-like structures within biological tissues and main applications of these methods. We especially focus on the research progress of spatial orientation information in important disease models, including wound healing, osteoarthritis, breast cancer, peritoneal metastasis, and brain injury. Additionally, we explore the relations between tissue structure and function via specific engineered tissues. A highly sensitive and highly accurate description of the fiber-like structures within biological tissues serves as a novel method for studying disease initiation and progression, shows potential for early disease diagnosis, and improves our understanding of the mechanisms underlying some disorders. Finally, future potential applications of the orientation analysis methods are explored.