Objective To study familial infectious status of helicobacter pylori (HP) and its effect on the rate of HP infection in children in the same household. Methods Children with abdominal pain and their parents were detected in the way of serology and 13 C -urea breath test (UBT). Results The HP infection rate of the family of 13 C-UBT and serologic HP-IgG was 41.6% and 76.5% respectively, higher than that of children with recurrent abdominal pain, which was 29.5% and 54.8% respectively (P<0.05 and P<0.005). The familial HP infection rate when children were HP positive by 13 C-UBT and serology was 83.7%and 85.7% respectively, much higher than that when children were HP negative, 23.9% and 65.3% respectively; the children's HP infection rates (59.4% using 13 C-UBT and 61.4% using serology) of the family with HP positive were also much higher than that of the family with HP negative, which was 8.3% using serology and with 33.3% using 13 C-UBT, (P<0.005). The sensitivity of serology was 94.2% , and the specificity was 36.1%. Conclusions The symptomatic infection rate of HP in children is high when there is HP infection in family members, 13 C-UBT better reflects the infectious status of HP in a particular family.