Quantification of T2 in areas bordering myocardium and blood pool is challenging due to partial volume errors. Blood signal suppression would effectively reduce partial volume effects and improve image contrast at the blood-myocardium boundaries. This study proposed a Black-blood hEart-rate Adaptive T2-prepared bSSFP (BEATS) sequence for myocardial T2 mapping to improve blood-myocardial border definition. Both phantom and in vivo studies proved the advantages of BEATS sequence compared to T2prep-bSSFP T2 mapping. The proposed BEATS sequence efficiently suppresses the blood signal, resulting in better definition of blood/myocardium border by reducing the impact of partial volume effect in T2 measurements, which improves the assessment of edema post myocardial infarction.