NTSC has been cooperating andexchanging with other time and astronomy laboratory all over the world since it was established. Through the essential cooperation and exchange with BIPM, NICT, USNO, IEN, TL, NML, PSB, Copenhagen University, etc., a lot of Scientific Research Results have been obtained. And NTSC also has been cooperating with the Pushchino Radio Astronomy Observatory of Russia about the study on X-ray millisecond pulsar timing.