Abstract: The myocardial inflammatory response is a fundamental pathological process in myocardial diseases, primarily characterized by myocardial cell necrosis and the infiltration of inflammatory cells. The role of inflammatory cells (lymphocytes, neutrophils, macrophages and so on) in the myocardial inflammatory response is critically important. Therefore, non-invasive detection of inflammatory cell infiltration within the myocardial inflammatory microenvironment is of significant importance for assessing the myocardial inflammatory response and monitoring the therapeutic efficacy of myocardial inflammation-related diseases. Integrated PET/MR imaging, which combines the metabolic imaging of PET with the anatomical imaging of MRI, is a molecular imaging technology that utilizes various molecular probes to comprehensively assess the myocardial inflammatory process. This approach provides imaging support for the diagnosis and therapeutic evaluation of myocardial inflammation-related diseases. Here, the authors systematically review the advancements in the application of PET/MR in evaluating myocardial inflammatory responses, with the aim of promoting the clinical application of PET/MR in myocardial inflammation assessment.