The invention relates to a heart rate variability (HRV) analysis method, apparatus and application. A low-cost, portable and wearable signal acquisition device is employed to obtain electrocardiography (ECG) signals of an epileptic patient within 24 hours before operation, the time domain, the frequency domain and the non-linear index of long-range and short-range ECG are calculated by means of a stylized HRV analysis method, based on the characteristic parameter representing the modulating effect degree of the vagus nerve to the heart rate, i.e., the vagus nerve activity, the curative effect of vagus nerve stimulation (VNS) operation to medically intractable epileptic patients is predicted accurately and efficiently, unnecessary appropriation expenditure is avoided, the optimal opportunity for treatment is prevented from being delayed, by means the HRV characteristic parameter of ECG, VNS operation indication patients are selected definitely, and the curative effect of the VNS therapy is improved on the whole.