A method for achieving short-distance unlocking according to an electrocardiogram, comprising 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 a short-distance communication by the wearable device to obtain an electrocardiogram of the user of the wearable device 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; wherein in the step A, the Bluetooth is adopted to search for whether the paired controlled device is within a first preset range, which specifically comprises: searching for whether a Bluetooth sensor of the paired controlled device is within the first preset range by a Bluetooth module of the wearable device; wherein if yes, then it is identified that the controlled device and the wearable device are in the short-distance state, and otherwise, it is identified that the controlled device and the wearable device are in the long-distance state; wherein the method is characterized in that, the step A specifically comprises: A1. transmitting a low-frequency signal by the Bluetooth module of the wearable device to, within a first preset time period, search for whether the Bluetooth sensor of the paired controlled device is within the first preset range, wherein if yes, then it is identified that the controlled device and the wearable device are in the short-distance state, and otherwise, it proceeds to the step A2; and A2. transmitting a high-frequency signal by the Bluetooth module of the wearable device to search for whether the Bluetooth sensor of the paired controlled device is within a second preset range, wherein if yes, then it is identified that the controlled device and the wearable device is in the long-distance state and it returns back to the step A1 immediately, and otherwise, it returns back to the step A1 after expiration of a second preset time period; wherein the first preset range is smaller than the second preset range, and the first preset time period is smaller than the second preset time period. 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 a short-distance communication by the wearable device to obtain an electrocardiogram of the user of the wearable device 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; searching for whether a Bluetooth sensor of the paired controlled device is within the first preset range by a Bluetooth module of the wearable device; wherein if yes, then it is identified that the controlled device and the wearable device are in the short-distance state, and otherwise, it is identified that the controlled device and the wearable device are in the long-distance state; wherein the method is characterized in that, the step A specifically comprises: A1. transmitting a low-frequency signal by the Bluetooth module of the wearable device to, within a first preset time period, search for whether the Bluetooth sensor of the paired controlled device is within the first preset range, wherein if yes, then it is identified that the controlled device and the wearable device are in the short-distance state, and otherwise, it proceeds to the step A2; and A2. transmitting a high-frequency signal by the Bluetooth module of the wearable device to search for whether the Bluetooth sensor of the paired controlled device is within a second preset range, wherein if yes, then it is identified that the controlled device and the wearable device is in the long-distance state and it returns back to the step A1 immediately, and otherwise, it returns back to the step A1 after expiration of a second preset time period; A1. transmitting a low-frequency signal by the Bluetooth module of the wearable device to, within a first preset time period, search for whether the Bluetooth sensor of the paired controlled device is within the first preset range, wherein if yes, then it is identified that the controlled device and the wearable device are in the short-distance state, and otherwise, it proceeds to the step A2; and A2. transmitting a high-frequency signal by the Bluetooth module of the wearable device to search for whether the Bluetooth sensor of the paired controlled device is within a second preset range, wherein if yes, then it is identified that the controlled device and the wearable device is in the long-distance state and it returns back to the step A1 immediately, and otherwise, it returns back to the step A1 after expiration of a second preset time period;