This paper proposes a new design of bi-directional, digital and miniaturized wireless endoscopy system through the analysis of the current wireless endoscopy systems. The presented system has some characterized features such as monitoring endoscopy image in real time, examination of the whole digestive tract, providing 3D range image data. All hardware modules in this design as well as their key technique are described in detail. The testing system based on FPGA is given out and the presented scheme has been verified. The digital-analog mix-mode chip in the capsule has been implemented in 0.18 μm CMOS process.