A method for recognizing a screen-off gesture, i.e. a pattern drawn by a user on a touch screen and to open an application without a bright screen, comprising: reading gesture data of the screen-off gesture from a touch chip for a set period when it is detected that a user inputs a screen-off gesture on the touch screen, wherein the gesture data includes gesture coordinates corresponding to the screen-off gesture, and wherein the touch chip is a processing unit included in said touch screen configured for communicating data with a CPU; determining, while reading said data from said touch chip, a screen-off gesture trajectory based on the gesture coordinates that have been read, when the gesture data satisfies a preset matching condition, which can be used to determine whether the gesture data is valid, and does not contain a preset end identifier, which includes an identifier set after all the gesture data have been totally read and configured to represent that the gesture data corresponding to the screen-off gesture have been totally read; comparing, while reading said gesture data from said touch chip, the screen-off gesture trajectory with each preset gesture trajectory in a preset gesture trajectory set; and stopping the reading operation of the gesture data when the screen-off gesture trajectory does not match any of the preset gesture trajectories in the preset gesture trajectory set; characterized by acquiring a sample screen-off gesture trajectory within a set time length when an update condition of the preset gesture trajectory set is satisfied; recognizing the sample screen-off trajectory as corresponding to one of the preset screen-off gesture trajectories; in response to said recognizing, dividing the sample screen-off gesture trajectory into at least two sample screen-off gesture sub-trajectories, and dividing the preset gesture trajectory corresponding to the sample screen-off gesture trajectory into the same number of sub-trajectories; comparing each sample screen-off gesture sub-trajectory with a corresponding preset gesture sub-trajectory having the same feature points as endpoints, and determining a deviation between the sample screen-off gesture sub-trajectory and the preset gesture sub-trajectory; and updating the preset gesture trajectory set by using the sample screen-off gesture trajectory when the deviation exceeds a set threshold. reading gesture data of the screen-off gesture from a touch chip for a set period when it is detected that a user inputs a screen-off gesture on the touch screen, wherein the gesture data includes gesture coordinates corresponding to the screen-off gesture, and wherein the touch chip is a processing unit included in said touch screen configured for communicating data with a CPU; determining, while reading said data from said touch chip, a screen-off gesture trajectory based on the gesture coordinates that have been read, when the gesture data satisfies a preset matching condition, which can be used to determine whether the gesture data is valid, and does not contain a preset end identifier, which includes an identifier set after all the gesture data have been totally read and configured to represent that the gesture data corresponding to the screen-off gesture have been totally read; comparing, while reading said gesture data from said touch chip, the screen-off gesture trajectory with each preset gesture trajectory in a preset gesture trajectory set; and stopping the reading operation of the gesture data when the screen-off gesture trajectory does not match any of the preset gesture trajectories in the preset gesture trajectory set; characterized by acquiring a sample screen-off gesture trajectory within a set time length when an update condition of the preset gesture trajectory set is satisfied; recognizing the sample screen-off trajectory as corresponding to one of the preset screen-off gesture trajectories; in response to said recognizing, dividing the sample screen-off gesture trajectory into at least two sample screen-off gesture sub-trajectories, and dividing the preset gesture trajectory corresponding to the sample screen-off gesture trajectory into the same number of sub-trajectories; comparing each sample screen-off gesture sub-trajectory with a corresponding preset gesture sub-trajectory having the same feature points as endpoints, and determining a deviation between the sample screen-off gesture sub-trajectory and the preset gesture sub-trajectory; and updating the preset gesture trajectory set by using the sample screen-off gesture trajectory when the deviation exceeds a set threshold.