Screen state control method and device

The invention relates to a screen state control method and device. The screen state control method comprises the steps of sending N times of ultrasonic wave sensing signals in a preset time period when an ultrasonic wave function of a terminal is detected to be opened, wherein N is an integer which is greater than 1; receiving returned ultrasonic wave receiving signals; successively judging whether the terminal is blocked or not according to the N times of ultrasonic wave sending signals and the corresponding ultrasonic wave receiving signals, and acquiring N judgment results; and determining that the terminal is blocked when at least one judgment result in the N judgment results refers that the terminal is blocked, and switching the screen state of the terminal from an open state into a closed state. According to the technical scheme, ultrasonic wave returned values are taken for multiple times successively within a certain time to judge whether the terminal is blocked or not, the judgment accuracy is improved, problems of misjudgment operations such as screen flickering caused by incorrect judgment in the prior art are overcome, and thus the user experience can be improved.