Abstract: In this paper, the theory and practice of transmission microwave OT performed by the authors are stated. How the various factors in microwave OT imaging effect the quality of image is discussed. The tomography scanner apparatus were established and OT-date of simple phantoms were collected. Using the reconstructive program, we nave got the microwave OT images. It is shown that we can get suitable image and resolution for low contrast objects, and valuable information for high contrast objects though the pseudomorph. appears seriously.