Abstract: In order to achieve borehole drilling along seam to detect all kinds of small geologic abnormal body and drilling gas pre-drainage along seam, we design drilling while drilling azimuth gamma logging that ensuring drill bit along coal seam. Compared with the traditional drilling monitoring instrument along seam, the logging tool adopting advanced technology of single-chip microcomputer and wireless transmission technology, can realize wireless MWD drilling along seam, which meets the requirements of the modern coalfield logging with reliability, real-time performance.