The reproductive system of Platevindex mortoni has been observed and studied in detail. The reproductive system is mainly composed of hermaphroditic gland, albumen gland, mucous gland, female reproductive system and male reproductive system. The female reproductive system was consisted of oviduct, spermatheca and vagina, and the male reproductive system was included vas deferens, seminal vesicle and penis. Compared with the reproductive system of Onchidium struma, find that they have some difference in the male reproductive system, the O. struma have a spiral penis with accessory penial gland while the Platevindex mortoni have a straight penis without any accessory gland. The anatomy of un-copulation individuals, find that their seminal vesicle were full of slender spermatozoa, while the spermatheca without any spermatozoa. The result shows that the mature own-spermatozoa were store in seminal vesicle. Anatomy of the copulationed individuals which act as a female role, their spermatheca were full of moving stubby spermatozoa, the result shows that the spermatheca were the place where donor- spermatozoa store. Vas deferens and male mating organ were observed in detail, and the transportation route of spermatozoa was also analyzed. The mature spermatozoa were transferred by hermaphrodite duct from hermaphroditic gland to seminal vesicle, then convey via vas deferens to penis, during the copulation, penis transport the spermatozoa to the vagina, finally enter spermatheca, when ova matured, transferred by oviduct to spermatheca, the sperm fertilized ova in the spermatheca.