The work focuses on investigation of spatial-temporal 3D vortex structure of a quasi twodimensional turbulent jet. Time-resolved tomographic PIV technique with repetition rate up to 10 kHz was used to measure 3D velocity distributions. It was shown that in quasi two-dimensional turbulent jet two types of coherent vortex structures exist. On the basis of instantaneous distributions of Q criterion 3D dynamics of vortex structure is studied. Longitudinal secondary vortex structures in far field of the quasi two-dimensional turbulent jet were detected for the first time.