A low-power digital baseband channel controller for bi-directional digital wireless endoscope capsule is presented and its implementation is described．The architecture and functions of the controller are designed for the asymmetric data-transmission system and the design was verified by both FPGA and(0.18um CMOS)ASIC Test results show that the controller has an operating frequency of 40 MHz and a data rate of 2 Mbps and it consumes 523uW of power when working．