Time-resolved optoacoustic technique offers a new ingredient in noninvasive monitoring of biological tissues. Due to the heterogeneous property of biotissue, different level of optical energy depositions generates different strength of the acoustic signal across the tissue. This makes it possible to probe the functional information tomographically inside the biological tissue. It becomes increasingly attractive as a hybrid non-invasive monitoring technique because it takes the advantages of high contrast feature delivered by the optical techniques and high penetration depth and resolution offered by the acoustical techniques. After a brief introduction of its theory, this paper reviews the state-of-the-art time-resolved optoacoustic methods that have been successfully applied in biomedicine, with a concentration on analytical monitoring and tomography.