A method for automatically switching a user interface of a handheld terminal device and a handheld terminal device are provided. The method in an embodiment of the present disclosure includes: obtaining a current state of the terminal device by using a first sensor, and obtaining current trigger states of touch sensors of the terminal device, where the current state is a horizontally holding state or a vertically holding state, and the touch sensors are set on the back and/or a side of the terminal device; determining a current holding mode of the terminal device according to the current state of the terminal device and the current trigger states of the touch sensors; and switching a user interface to a user interface corresponding to the current holding mode of the terminal device. An embodiment of the present disclosure further discloses the handheld terminal device.