A whole varicella virus antigen-ELISA method was used to investigate the sera prevalence rate of varicella in 315 healthy children aged 3-7 years. Results showed that the sera positive rate of anti-VZV-IgG was 41.6%. Different prevalence rates in different kindergartens were noticed, characterizing the differences of populations. Immunogenicity of Oka strain attenuated varicella vaccine among children was also studied. No obvious adverse reactions were observed and the seraconversion rate was 85.1%.