Abstract: Five hundred and eight serum-negative volunteers with ALT normal, 4-18years old have heen selected from four trial fields and inoculated with five different lots of live attenuated hepatitis Avaccine.Within 3 days, no local and systematic abnorxnalitv as well as within 1 month no side effect related to hepatitis was observed. The rates of seroconversion reached 88.7%一91.5% 8-12 weeks postinoculation arid GMTs were 2.73- 4.88. The seroconversion rates of HAV lgM for 3-5 weeks were 3.6%一18.1%.The human diploid cells KMB 17 was used to isolate HAV in fecest With 205 samplescollected from 32 volunteers, 98 30 showed positive the rates of isolation and fecal virus-s heclding reached 47.8% and 93.8% repectively.