This study is based on rat model of MI/RI, DCs intervention experiment, DCs and myocardial cell co‐culture experiment, HMGB1, HMGB1 antibody and TLR4 antagonists treatment, to explore the effect of HMGB1/TLR4 pathway on DCs function and its mechanism, to provide ideas and theoretical basis for the prevention and treatment of MI/RI. Here, TLR4 is linked to myocardial infarction.