The horseshoe crab, Tachypleus tridentatus, is known as a living fossil. It plays a veryimportant role in evolution and medical resarch. Tachypleus tridentatus once istributedwidely along the west coast of Taiwan island decades ago. It is almost eliminated fromthe coast as a result of pollution and degradation. In Taiwan, Tachypleus tridentatus,canonly be found in Kimmen and Penghu island. Tachypleus tridentatus in Penghu is facingsurvival crisis. Thus, conservation need to be done in no time. The objectives of thisstudy are establishment of genetic stock and cultural techniques of Tachypleustridentatus. The stock will be collected and preserved for utilization of researchers. Thetank system, diet, growth, mature size, spawning season, embryonic development,hatching, and larvae rearing will be studies. The knowledge will be very valuable for themass seed production.