As a new technique of determining the viscoelasticity of soft biomaterials and cell cytoplasm in living cells, particle tracking microrheology (PTM) is mainly applied in the biomechanical research field, such as cell movement, embryo development, laminopathies. PTM has many advantages over the conventional detection methods in cell mechanics. Using this technique, the Brownian motion of probe particles embedded in the medium could be measured by the video-microscopy, and the movement trajectories of the probe could be mathematically transformed into the mean squared displacements (MSDs) thus to extract the parameters such as the frequency-dependent viscoelastic modulus or the creep compliance from the time dependent MSDs of the probes. The basic principles of PTM technique and its application in biomechanics will be reviewed in this paper.