A full-field optical coherence tomography (FF-OCT) system is reported, which has the capability of generating in vivo optical sectional images. The system is based on a Linnik white light interference microscope illuminated by tungsten halogen lamps, in which identical microscope objectives are used for both illumination and detection in reference and sample arms. Measured axial and lateral resolution of the developed system is 1.3 μm and 0.89 μm respectively. A 640 pixel × 480 pixel CCD camera is used to capture interference signals with imaging depth of 80 μm. A single chip-based control system is developed to modulate phase between both arms with the intention of higher signal-to-noise ratio (SNR) and faster acquisition speed, en face and 3D images of onion cells are presented, acquisition time is reduced from 60 s to 4 s per en face image and the SNR is improved from 18.36 dB to 23.30 dB compared with the system without it. The spherical aberration introduced by high-numerical aperture objectives and refractive index mismatch is considered theoretically and a compensation method is proposed. After compensating the spherical aberration experimentally, more details are shown in the en face images of onion cells (SNR is improved from 25.41 dB to 29.54 dB). Cell-level in vivo images of human finger skin are also presented. The imaging of liver tissue is performed, which demonstrates the potential value of FF-OCT in the early diagnosis of cancer. The apparatus proposed and developed will be helpful for the design of the practical device as a fast diagnostic means instead of the traditional frozen-section method.