The invention relates to the technical field of measurement-while-drilling instruments for petroleum drilling, in particular to a connecting nipple of a logging-while-drilling instrument. The connecting nipple is mainly composed of a copper ring, an inner sealing ring of the copper ring, a connecting nipple body, a sealing joint, an outer sealing ring of the copper ring and a sealing joint sealingring, wherein the copper ring and the sealing joint are arranged at the two ends of the connecting nipple body correspondingly, and corresponding center adapting joints and side wall single-core pinsare installed on the two sides of the connecting nipple correspondingly. The side, where the center adapting joints are installed, of the connecting nipple body adopts a circumferential hole distribution design, seven small flow-through holes are symmetrically formed, the size of the small flow-through holes is consistent with the size of large flow-through holes in the side where the side wall single-core pins are installed, and transition holes with a larger flow-through area are formed between the large flow-through holes and the small flow-through holes. According to the connecting nipple, the matching use of logging-while-drilling instruments with different structures is realized, flow-through hole passages are optimized, the eddy current effect of flow-through slurry caused by the change of the flow-through area is effectively reduced, and the underground service life of the connecting nipple and the matching connected logging-while-drilling instrument can be effectively prolonged.