A vascular fiber optic guide wire (10), comprising at least one fiber optic core wire, wire winding layers (13), and hydrophilic coatings (14) capable of improving the body fluid compatibility and reducing resistance. The fiber optic core wires are provided at an axis of the fiber optic guide wire (10). A wire winding layer (13) consists of at least one winding wire or a winding sheet (131) which wraps and surrounds the fiber optic core wire. A hydrophilic coating (14) is coated at the periphery of the wire winding layer (13). The fiber optic guide wire (10) can enter a predetermined position of an artery blood vessel of a human body and lead light into and/or out of a lesion part to realize photodynamic therapy for in vivo tumors and the like so as to meet diagnosis and treatment requirements in the field of biology and medicines.