An application method of an accelerometer, wherein the method comprises the following steps to enable utilization of an existing structure of the accelerometer itself to function also as pressure sensor for achieving dual usage of the accelerometer as both inertial sensor and pressure sensor: processing a detection signal of the accelerometer, wherein based on an influence of a strain deforming an external housing of the accelerometer, generated under an action of an external force, the detection signal is adapted to reflect the external force, wherein the accelerometer comprises a detection capacitor, wherein the detection signal is equivalent to a capacitance measurement value defined by the detection capacitor, wherein acceleration and the external force are reflected by the capacitance measurement value, wherein the detection capacitor comprises a first detection capacitor and a second detection capacitor, wherein the first detection capacitor defines a first capacitance measurement value (C 1), and the second detection capacitor defines a second capacitance measurement value (C 2), wherein the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2) are changed in opposite directions, wherein the acceleration is reflected by a difference between the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2), wherein when the strain is generated on the accelerometer, the external force is reflected by a corresponding change of the first capacitance measurement value (C 1) and/or the second capacitance measurement value (C 2); converting the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2) into a detection item by an operation, wherein a detection reference limit is set; and in response to the detection item exceeding the detection reference limit or a threshold value set based on the detection reference limit, determining that the external housing of the accelerometer is deformed due to the external force. processing a detection signal of the accelerometer, wherein based on an influence of a strain deforming an external housing of the accelerometer, generated under an action of an external force, the detection signal is adapted to reflect the external force, wherein the accelerometer comprises a detection capacitor, wherein the detection signal is equivalent to a capacitance measurement value defined by the detection capacitor, wherein acceleration and the external force are reflected by the capacitance measurement value, wherein the detection capacitor comprises a first detection capacitor and a second detection capacitor, wherein the first detection capacitor defines a first capacitance measurement value (C 1), and the second detection capacitor defines a second capacitance measurement value (C 2), wherein the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2) are changed in opposite directions, wherein the acceleration is reflected by a difference between the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2), wherein when the strain is generated on the accelerometer, the external force is reflected by a corresponding change of the first capacitance measurement value (C 1) and/or the second capacitance measurement value (C 2); converting the first capacitance measurement value (C 1) and the second capacitance measurement value (C 2) into a detection item by an operation, wherein a detection reference limit is set; and in response to the detection item exceeding the detection reference limit or a threshold value set based on the detection reference limit, determining that the external housing of the accelerometer is deformed due to the external force.