A new method for realizing the optical tomography of bio-tissue by using a δ sound field and a near infrared laser is presented. A δ sound field is cons tructed and is acted upon the tissue, and this causes some variations of optical properties at the action spot . A perturbation of the light intensity distribution on the tissue surface is measured. The inherent relations between the perturbation and the variations of optical properties are discussed. The optical property distribution in the tissue volume can be extracted from the light distributions on the tissue surface by scanning the action spot at the layer to be constructed. The present method is useful for clinic applications and diagnoses of breast cancers at early stage.