Calcifications in the calcified focuses from inflammation and hyperplasia of breast patients were investigated in terms of their composition, structure and morphology by using light microscope (OM), environmental scanning electron microscope (ESEM) and micro area X-ray diffraction (BL15U), and the formation mechanism of the calcifications was discussed. The results show that the calcifications in inflammation focus mainly result from dead adipocytes and repairing collagen of type Ⅲ which occurs at the late stage of the disease. Dilating catheter calcifications in hyperplasia of breast come from collagen of type Ⅳ. At the early stage of thanatosis calcification of hyperplasia, many nano-sized calcified balls are precipitated on the collagen fibers of type Ⅳ due to the adsorption of inorganic ions such as calcium ions onto glucose amino glycan. These balls continue to grow and aggregate, and gradually act as the calcification of the collagen fibers during the development of the disease, which finally turns out to be a large area. The main component of calcifications of both inflammation and hyperplasia of breast is poorly-crystallized carbonate-rich hydroxylapatite.