Abstract: Objective To investigate the change of leukocyte volume conductivity scatter（VCS） parameters in patients with A/H1N1 and its value in accessory diagnosis of A/H1N1. Methods Leukocyte VCS parameters were detected with the Coulter LH750 automatic hematology analyzer in A/H1NI patients（experimental group） diagnosed by gene amplification and healthy individuals（control group）. Results The MMV and MLS of VCS parameters were significantly higher in experimental group than in control group（171.615±9.156 vs 157.157±10.026, 62.003±6.916 vs 54.263±3.817, P＜0.001）, while the MNS of VCS parameters was significantly lower in experimental group than in control group （114.946±1.603 vs 154.263±3.817, P＜0.001）. Conclusion VCS parameters are changed differently in A/H1N1 patients and healthy individuals, which is of certain reference value for the early diagnosis of A/H1N1.