The visualization of a quasi-stable flow field with full 3-D meaning must be provided with 2-D projections. In flow field interferometric tomography, the conventional method of fringe tracking, by which a few solitary 1-D projections are obtained, can evaluate only the 2-D distribution of the field on a limited number of cross sections. A new method that combines Fourier analysis and modified multigrid iteration is proposed to extract 2-D projections from interferograms of the measured field in various directions. On the basis of 2-D projections, the real 3-D field reconstruction can be realized. An experiment with an asymmetric temperature field measurement using a rotary Fabry-Pe´ rot (F-P) interferometer is reported and some cross sections of the reconstructed temperature field are given to prove that the methods of sampling, processing and reconstruction of the algorithm illustrated are effective.