Abstract: An attenuated vaccine strain(MPV-P1) of Muscovy duckling parvovirus(MPV)was obtained from putian strain of MPV by biotechnolog y.The MPV-P1 was non pathogenicity to one-day old muscovy ducks.Its immuno genicity and genetic stability were excellent.The vacine was prepared in MDEF cells with MPV-P1 strain.The third day after vaccination,part of the muscovy ducks appeared against MPV antibody,all of them appeared to MPV antibody within 7 days.The peak titer of the antibody reached on 21-30 days after vacination.The period of effective immunization was more than 190 day s.The pro tectiv e r ate w as 100%w hen challeng ed w ith MPV on 7 days after vaccination.When the muscovy ducks had LPAI titers of 1.0(Log 2)or more,almost all of them were protected.To compare both vaccination,the results indicated that intr amuscular injection is more effective than nasal drop.W hen the frozen dry vaccine was stored at 22℃for 6 months,at 4-8℃for 12 months and at 20℃fo r 12 months r espectiv ely,its im- mune activity was noremar kable change.The results of the field trial of 180 millio ns of muscovy ducks(one-day-old)vaccinated in Fujian,Guang dong,Guangxi,Zhejiang and other provinces showed that noside effects or clinical singns occured.These results above revealed that this vaccine had good safety and efficacy.