Objective To explore the effect and mechanism of sphingosine-1-phosphate (S1P) on the development of arrhythmia after autologous myoblasts transplantation.Methods Arrhythmia was induced by procedural stimulation, and Ca²⁺ concentration was measured by Ca²⁺-ATPase activity in myocardial tissue. Rat cardiomyocytes were isolated and cultured in vitro, and co-cultured with skeletal muscle myoblasts to construct a hypoxia/reoxygenation injury model. S1P intervention was started with the reoxygenation phase, and the protein expression of Connexin43 (Cx43) was detected by Western blotting and immunohistochemistry. Thus, to clarify the effect of S1P on arrhythmia after myoblast transplantation for myocardial infarction, and initially explore the mechanism of S1P in reducing arrhythmia after cell transplantation.Results The onset of arrhythmia in the S1P cell transplant group was not only delayed, but the induction rate was decreased, and the duration was shorter than that in the control group (P < 0.05). Ca²⁺-ATPase activity was higher in cells transplanted into S1P than in cells transplanted alone (P < 0.05). In the hypoxia/ reoxygenation injury model of isolated myoblasts and cardiomyocytes, Cx43 protein expression increased significantly with increasing S1P (P < 0.05).Conclusions S1P promotes the development of Ca²⁺-ATPase activity and gap link Cx43 protein through myocardial ischemia and reperfusion, thus reducing the occurrence of ventricular arrhythmia after cell transplantation.