The invention is aimed at providing an optical fiber integrated with an optical coherence and incoherence imaging system and an imaging method. A low coherence optical interference technology is adopted for the OCT (optical coherence tomography), and a single-mode optical fiber needs to be used for transmitting and receiving optical signals. A multi-mode optical fiber is suitable for incoherence spectroscopic imaging. Single-mode transmission and multi-mode transmission are achieved at the same time on the single optical fiber, then two or more imaging modes are integrated for combined imaging, and the advantages of two or more types of imaging can be combined. The invention provides the three-cladding optical fiber and the imaging method. The optical fiber is composed of a fiber core and three claddings. The three claddings include a fiber core layer (also called an inner layer fiber core) for single-mode transmission, a first cladding (also called an inner layer cladding), a second cladding (also called an outer layer fiber core) for multi-mode transmission, and a third cladding (also called an outer layer cladding).