【Objective】 To investigate the deferral causes of voluntary blood donors in primary blood screening in Hangzhou, so as to take steps to reduce the deferral rate. 【Methods】 The causes of donor deferral in 8 blood donation sites in Hangzhou from January 2019 to December 2020 was statistically analyzed. 【Results】 A total of 103 325 donors(49 335 in 2019, 53 990 in 2020)were registered in 8 blood donation sites in Hangzhou From 2019 to 2020, among which 87 435 (44 462 in 2019, 42 973 in 2020)were successfully donated, and 15 890 (4 873 in 2019, 11 017 in 2020) were deferred, with a deferral rate of 15.38%(9.88% in 2019, 20.41% in 2020). The main reasons leading to donation deferral were Alt, medical history and lipemic blood. Significant differences were noticed in deferral items as medical history, HBsAg, TP, ALT and lipemic blood by gender and donation history, and not in Hb by gender. 【Conclusion】 Promoted publicity, specified primary blood screening, especially the pre-donationTP detection can effectively reduce the proportion of high-risk blood donors, cut down blood deferral rate, thus avoiding the waste of blood resources and balancing blood supply and demand.