Optical phase conjugation(OPC) is a technique that generates a light field with reversed wavefront and identical amplitude distribution as the incident light. It has a unique feature of suppressing the aberration of incident beam induced by inhomogeneous or disturbing medium. Although this technique has been extensively studied since the 1970s, it has become more attractive because of unprecedented achievements and prospective potentials in biomedical applications. OPC-based techniques have been successfully utilized to form a focus through/inside highly scattered biological samples. It opens a new avenue by significantly enhancing the light delivery in biological tissue for high-resolution imaging, diagnosis and treatment of medical diseases. In order to provide insight into its further development, recent progress of OPC techniques for focusing light through/inside biological tissue was summarized.