The invention discloses a single photo based three-dimensional face modeling method and system. The modeling method is characterized in that a deformation model is acquired through dense point correspondence and principal component analysis, and then a face model is built through feature point alignment. The beneficial effects are that 1) compared with a three-dimensional scanner, the modeling method is good in universality and flexibility, simple to operate, low in cost and applicable to the general public; 2) compared with multi-face-photo modeling, the modeling method simplifies manual operation steps and reduces the computation time; and 3) compared with traditional single-face-photo modeling, the modeling method only needs simple manual initialization, the computation amount is small, the face modeling speed is high, and an acquired face model is high in sense of reality. The modeling system comprises an image acquisition module, a conversion module, an analysis module, a molding module and a Face++API interface. The modeling system further has the beneficial effects that 1) a generated face model has a strong sense of reality, the modeling time is short, and the automation degree is high.