In order to reduce the power consumption and increase the lifetime of the wireless endoscopic system, a digital-analog mix-mode ASIC for baseband processing is proposed in this paper. Near-lossless image compression, bi-directional communication and power management modules are integrated in the chip. The image compression algorithm is composed of an image filter and JPEG-LS encoder, by which the images with raw Bayer color filter array pattern can be real-time compressed. The design has been successfully verified on FPGA and fabricated in 0.18μm CMOS technology. The test result shows that the overall power consumption is reduced by 48%.