Method for determining target point and positioning system of mammography system

The invention provides a method for determining a target point and a positioning system of a mammography system. In a first stereotactic image and a second stereotactic image of a target suspected focus, each suspected focus is marked in the first stereotactic image and the second stereotactic image, a plurality of alternative puncture point pairs are obtained, spatial three-dimensional coordinates corresponding to the alternative puncture points are obtained, and the target suspected focus is obtained through the spatial three-dimensional coordinates. And obtaining a two-dimensional plane distribution diagram containing the third-dimensional direction of each pair of alternative puncture points, and determining a target point according to the two-dimensional plane distribution diagram, the first three-dimensional positioning image and the second three-dimensional positioning image. The positioning system of the mammary gland X-ray photography system can obtain the two-dimensional plane image containing the t