Introduction: Acute kidney injury (AKI) leads to electrolyte imbalances, particularly in blood K+ and Ca2+ levels. These electrolyte disturbances can directly affect cardiac electrophysiology, potentially causing arrhythmia. However, the specific ECG features associated with early-stage AKI development remain unclear. There is a lack of non-invasive biomarkers for warning of cardiac injury during the initial phases of AKI. Methods: The relationship between cardiac electrophysiological properties and AKI development was established through electrolyte changes. Serum K+ and Ca2+ levels in mice were measured at 1, 3, 6, and 12 hours post-AKI onset. These electrolyte values were input as parameters into cardiac computational model to simulate the ECG during the early stages of AKI. A one-dimensional transmural ventricular model of the mouse was constructed, incorporating endocardial, middle, and epicardial layers. The middle layer cell model was designed to simulate the long plateau phase, consistent with previous experimental observations. The ECG of the fiber model was simulated by superimposing electrical signals of these three layers in one heartbeat. Results: Experimental results show that serum K+ and Ca2+ levels decrease initially in 1-hour post-AKI, followed by a continuous increase over the next 12 hours. In silico study, low serum K+ leads to hyperpolarization, resulting in increased R and S wave amplitudes during the 1-hour post-AKI phase. In the 12-hour post-AKI phase, high serum K+ causes electrical conduction delay and depolarization, manifesting as prolonged QRS duration and decreased R and S wave amplitudes. The T wave peak, corresponding to the action potential duration plateau phase, is delayed. Conclusion: Electrolyte alterations within 12 hours of AKI onset induce observable changes in the ECG. This indicates the existence of a mapping relationship between ECG characteristics and AKI development. ECG may serve as a valuable non-invasive clinical biomarker for identifying cardiac injury in the early stages of AKI.