Abstract: The oocysts of two species of plasmodia,P.gallinaceum and P, yoelii yoelii were cultured in Mit suhashi and Maramorosh medium (M-M medium,1964) and the medium modified by increasing the amount of some amino acids and raising the osmotic pressure.The result showed that the 7-day old oocyst of P.gallinaceum and the 8-day old oocyst of P.yoelii yoelii could release sporozoites after 3 to 4 day's cultivation in modified M-M medium.The sporozoites were mautre in morphology. We found that the contamination rate in cultivating the stomach of Anopheles stephensi was much higher than that in cultivating the stomach of Aedes albopictus, although the same method of steri-lizing the stomach of mosquito had been used.