The invention aims to provide an SNP (Single Nucleotide Polymorphism) site used for detecting an acute hemolytic transfusion reaction caused by the A-type variants of an ABO blood-group system, and isthe basic groups of 467th, 499th,527th and 1061st sites of an A-type variant gene coding area from an initiation codon. The invention provides a new purpose of an A-type variant gene so as to providean effective approach capable of carrying out quick gene diagnosis, genetic screening and genetic counseling on acute intravascular hemolytic transfusion reaction, and an application effect indicatesthat a gene SNP site and a detection primer provided by the invention can be effectively used for quickly detecting the new A-type variant gene mutation sites of the peripheral blood of a clinic patient.