The invention provides a method for observing a cavity through body surface projection virtual transparency in a minimally invasive surgery, and belongs to the technical field of medicine, three-dimensional stereo imaging, digital image processing and the like. The method for observing a cavity through body surface projection virtual transparency in a minimally invasive surgery comprises contentsin three respects of a doctor visual angle tracing method, a cavity three-dimensional modeling method and a patient body surface projection image sequence generating method. The technique is applied to a system for observing the cavity through the body surface projection virtual transparency of the minimally invasive surgery, and plans to be targeted for a patient body surface having a non-quadricsurface, a doctor visual angle and a cavity three-dimensional model are combined, a body surface projection cavity image is generated, real virtual abdomen transparent effects are obtained, and finally, the purpose that under the premise that a doctor and the surgery environment are not influenced, the requirement of the doctor for auxiliary observation of the cavity in an ordinary minimally invasive surgery is met can be realized.