Abstract: The morphology and structure of thelycum and sperm storage in Penaeus chinensis and Trachypenaeus curvirostris were studied using laser scanning confocal microscope .They all have closed thelycum.The thelycum of T .Curvirostris is covered with fore-and-aft two carapace slices , between the slices in center aperture , which is usually stoppered by jelly substance after male .At the center of thelycum is one single cavity and there are two sack-like vesicle at rear end of thelycum in which sperm sacs are stored .The thelycum of P .chinensis has single cavity covered with two semi-round , right-left symmetry carapace slices .There are three tapers shaped prominences stick out from front into the cavity .In maled female Chinese shrimp , the prominences were mosaicked into spermatophore , which could firm the spermatophore .