Background: Myocardial infarction is 1 of the most serious cardiovascular diseases. Early interventional therapy preserves the cardiac function of patients with myocardial infarction to the greatest extent, but it is far from meeting people's need only limited to cardiac revascularization. It is also necessary to help patients improve their quality of life, exercise tolerance, and reduce the incidence of acute cardiac recurrence as much as possible. All these depend on cardiac rehabilitation (CR) are based on exercise. Early and correct CR helps to improve the patient's heart function and improve living standards. Traditional Chinese exercise Tai Chi as an alternative form of CR has gradually become popular, but it lacks large samples and high-quality clinical studies to verify it. This study aims to explore the effect of Tai Chi on the cardiac function of patients with myocardial infarction, and to provide a strong basis for patients to choose which CR exercise. Methods: This is a prospective randomized controlled trial. 272 patients with myocardial infarction will be randomly divided into an experimental group and a control group according to 1:1, with 136 cases in each group. The control group: conventional treatment; the experimental group: increase Tai Chi exercise on the basis of the control group. Both groups will receive standard treatment for 24 weeks and will be followed up for 3 months. Observation indicators include: total effective rate, 6 minutes walking test, brain natriuretic peptide, left ventricular ejection fraction, the adverse reaction rate, etc. The data will be analyzed by using SPSS 25.0 software. Discussion: This study will evaluate the effect of Tai Chi on the cardiac function of patients with myocardial infarction. The results of this test will provide clinical evidence for patients to choose which CR exercise.