The invention discloses a method for detecting a single-pixel blood vessel, and belongs to the technical fields of medicine, three-dimensional imaging, digital image processing and the like. Accordingto the method, Frangi blood vessel characteristic F characteristic parameters are calculated firstly, then the Frangi blood vessel characteristic quantity F is replaced with a blood vessel characteristic center line, and finally in order to overcome a large number of misjudgments caused by microvessels or background noise, the center line R is calculated in a weighted mode; according to the method for detecting the single-pixel blood vessel, a weighted calculation center line is adopted, so that the influence of microvessel and background noise can be inhibited; the technology is applied to abody surface projection virtual transparent observation inner cavity method in a minimally invasive surgery provided by an applicant. As a core part of the three-dimensional modeling method for the inner cavity in the method, the method lays a solid theoretical foundation for obtaining a more real virtual abdominal cavity transparent effect and meeting the requirement of doctors for assisting inobserving the inner cavity in a common minimally invasive surgery on the premise of not influencing the doctors and the operation environment.