Abstract: Objective　To explore the effect of parvovirus B19 (VB19) infection on pediatric leukemia patients. Methods The pediatric leukemia patients were enrolled in the study in the Children's Hospital of Soochow University. Expression levels of VB19-DNA-PCR were detected using the polymerase chain reaction. Positive patients would be monitored and treated by conventional treatment as well until VB19 gene became negative. The data was compared according to the VB19 clearance time, clinical symptoms and blood counts to evaluate the effect. Results　In the 3009 samples from 824 pediatric leukemia patients, there were 36 samples (1.2%) from 12 cases (1.5%) of pediatric leukemia paients with positive VB19 infection. Among the positive patients, 11 cases (1.9%) were from 582 with acute lymphoblastic leukemia (ALL) patients and 1 (0.45%) was from 212 with acute myeloid leukemia (AML). According to the treatment stage, 3 cases were in initially diagnosed period, 2 cases in early stage of consolidation chemotherapy, 4 cases in delayed enhanced chemotherapy period, and 3 cases in maintenance chemotherapy period. According to the treatment response, 4 cases were in continuous treatment, 2 cases were sensitive to treatment, and 3 cases were drug resistant. In the drug resistance group, 2 cases developed into the pure red cell aplastic anemia (PRCA). After treatment, one was recovered from PRCA with VB19 cleared, the other one remained PRCA with continuously positive VB19. Conclusions　More VB19 virus infection in pediatric ALL happened in delayed enhanced chemotherapy period. The persistent presence of VB19 infection on pediatric leukemia patients is closely related with PRCA.