Abstract: An imaging method for microcalcification displays microcalcification distribution by acquiring and overlapping a photoacoustic image of microcalcification and an ultrasonic image of tissue. The image acquired by the present invention, in comparison to images acquired by ultrasonic and X-ray mammography, has advantages in no speckle noises, higher optical contrast, higher ultrasonic resolution, and so on. The present invention also has advantage in safety by adopting a light source having no ionizing radiation. An imaging method for diagnosing breast cancer is also herein disclosed.