The horseshoe crab, Tachypleus tridentatus, is known as a living fossil.It plays a very important role in evolution and medical resarch.Tachypleus tridentatus once istributed widely along the west coast of Taiwan island decades ago. It is almost eliminated from the coast as a r e s u l t o f p o l l u t i o n a n d d e g r a d a t i o n . I n T a i w a n , T a c h y p l e u s tridentatus,can only be found in Kimmen and Penghu island. Tachypleus tridentatus in Penghu is facing survival crisis. Thus, conservation need to be done in no time. The objectives of this study are establishment of genetic stock and cultural techniques of Tachypleustridentatus. The stock will be collected and preserved for utilization of researchers. The tank system, diet, growth, mature size, spawning season, embryonic development,hatching, and larvae rearing will be studies. The knowledge will be very aluable for the mass seed production.