A method for achieving short-distance unlocking according to the electrocardiogram and a system thereof are disclosed. The method comprises the following steps of: A. when a paired controlled device is found by a wearable device, determining by the wearable device whether the controlled device and the wearable device are in a short-distance state or a long-distance state therebetween; B. if the controlled device and the wearable device are in the short-distance state therebetween, then activating the short-distance communication by the wearable device to obtain the user's electrocardiogram and to wirelessly transmit the electrocardiogram to the paired controlled device; and C. determining by the paired controlled device whether the received electrocardiogram matches a template electrocardiogram stored in the paired controlled device, wherein if the received electrocardiogram matches the template electrocardiogram, then the controlled device is unlocked automatically.