【Objective】 To observe and analyze the detection results of blood type unexpected antibody and its risk factors in inpatients, so as to provide reference for promoting the safety of clinical blood transfusion. 【Methods】 Clinical data of 22 800 inpatients were collected retrospectively and unexpected antibody screening was performed by microcolumn gel method and saline method. According to the screening results, the inpatients were divided into positive group (n = 62) and negative group (n = 22 738). Clinical data of the two groups were collected and analized by univariate analysis, and specificity identification of unexpected antibody was performed in the positive group. The specific distribution characteristics of antibody were statistically analyzed, and the risk factors of unexpected antibody were analyzed by binary logistic regression. 【Results】 Among the 22 800 inpatients, the yield rate of unexpected antibody was 0.27% (62/22 800), with Rh, MNS, Lewis, Kidd blood group antibody, mixed antibody, autoantibodies and others accounted for 40.32% (25/62), 14.52% (9/62), 6.45%(4/62), 1.61%(1/62), 20.97%(13/62), 6.45%(4/62) and 9.68%(6/62), respectively. Univariate analysis showed that there were significant differences in gender, age, pregnancy history, blood transfusion history, blood transfusion frequency and disease type between the positive group and the negative group by chi-square test (χ² = 11.142, 6.994, 12.453, 4.762, 5.493, 92.381, all P<0.05), while there was no significant difference in nationality (χ² = 3.719, P>0.05 ) . Binary logistic regression analysis showed that female, age >60 years old, with history of blood transfusion, number of blood transfusion >3 times, history of pregnancy, solid tumor and blood diseases, severe internal medical diseases were independent risk factors for unexpected antibody(P<0.05) . 【Conclusion】 For patients who need blood transfusion, especially those with the above risk factors, conducting unexpected antibodies screening and identification before transfusion, avoiding corresponding antibodies and selecting antigen-negative blood for cross-matching were suggested to ensure the effectiveness and safety of clinical blood transfusion.