【Abstract】 Objective To explore the feasibility of the treatment of ischemic heart disease by delivery of Bone marrow mesenchymal stem cells (MSCs) using needlefree injection.Methods 32 dogs were randomly divided into 4 groups. Before operation, acute myocardial infarction model was produced by ligation of the left anterior descending coronary artery. No treatment, delivery of normal saline using needlefree injection, delivery of stem cells using needle injection and delivery of stem cells using needlefree injection was respectively done at the myocardial infarction area in the 4 groups. Hemodynamic monitoring was performed after 6 weeks treatment. The hearts were harvested and sectioned for histological and immunohistochemical detection. The farction size and the number of small vessels were measured after the animals were sacrificed.Results Compared with other groups, the left ventricular end diastolic pressure (900±32mmHg) was decreased. The maximum rise rate (84186±7285 mmHg/s) and the maximum decline rate (78729±4508 mmHg/s) of left ventricular pressure were increased. The infarct size (1859±358%) was decreased and the number of newborn small vessels (957±223) increased in the group with delivery of stem cells using needlefree injection（P＜005）. Conclusions It is safe and effective to treat the ischemic heart disease with the needlefree injection of stem cells.