Provided are a volume adjustment and control device and method for a mobile terminal, and a mobile terminal. The method comprises: detecting a press parameter of a hardware trigger button; according to a detected state, judging whether a pre-determined activation condition is satisfied, so as to obtain a judgement result; when the judgement result indicates that the activation condition is satisfied, activating a gravity sensor; acquiring detection data of the gravity sensor; and according to the detection data of the gravity sensor, adjusting the volume. The device comprises a detection module, a judgement module, a starting module, an acquisition module and an adjustment module. The device is installed in the mobile terminal. By means of the present invention, the detection data of the gravity sensor is collected, and the volume of the mobile terminal is adjusted according to the corresponding relationship between the detection data of the gravity sensor and the volume. The present invention is simpler and more convenient in operation, thereby improving the operation experience of a user. The mobile terminal can achieve the adjustment of volume by setting a volume adjustment key, so that the mobile terminal is simpler and conforms to the development trend of mobile terminals.