Objective In order to know the changes of serum pertussis IgG antibody level and the percent-age of white blood cells and lymphocytes in blood routine of children with IgG antibody positive,it is easy to diagnose and treat according to the clinical symptoms and examination results of children.Methods 485 cases of children in Shangdong Provincial Hospital were randomly enrolled as the test subjects,and pertussis anti-body IgG(PT -IgG)detection and blood cell detection were carried out.Results The levels of Pertussis IgG antibody were positive in 90 cases,the positive rate was 18.6%,pertussis IgG antibody level of children aged 8- <10 years old was the highest,2- <4 years old took the second place,10-14 years old were with the low-est levels.Among the patients with positive pertussis antibody levels,white blood cells in total were more than 20×109/L and lymphocyte percentage reached more than 60% in 19 cases,the positive rate was 21.1%,of which 6- <8 years old the highest positive rate was 10-14,the lowest.Conclusion IgG antibody of pertussis incidence is higher in children under 10 years old,the changes of white blood cells and lymphocytes mainly in children under the age of 8,the general course of the disease can be up to 2-3 months,so the need for early diagnosis and treatment,strengthen the immunity of pertussis vaccine is very necessary for children.