A transmission full-field microscope of cryo-soft X-ray tomography (SXT) was developed as a platform to image three-dimensional frozen hydrated cells in beamline TPS 24A at Taiwan Photon Source (TPS). This microscope consists of two main compositions in a vacuum chamber: The first composition is the optical system of the microscope, and the second composition is the cryogenic cooling system. The optical system includes a high demagnification capillary condenser and an objective of Fresnel zone plate. The cryogenic cooling system consists of sample transferring, robot and rotational sample systems. In our preliminary results, a spatial resolution of around 25∼30 nm half-pitch was obtained from a 2D image of standard calibration Nested L sample, and a clear crista of inner membrane in mitochondria from a frozen lung carcinoma cell was imaged at water window energy of 520 eV. [ABSTRACT FROM AUTHOR]