The invention discloses a method and device for controlling an unmanned vehicle. One specific embodiment of the method includes the steps that driving environment information of the unmanned vehicle is acquired; the driving environment information is guided in a pre-trained control instruction determining model for matching to obtain a control instruction of lamplight or a horn, wherein the control instruction determining model is used for representing the corresponding relationship between the driving environment information and the control instruction of the lamplight or the horn; the lamplight or the horn of the unmanned vehicle is controlled according to the control instruction of the lamplight or the horn. According to the embodiment, automatic control over the lamplight or the horn of the unmanned vehicle is achieved, therefore, enough prompting can be given to surrounding pedestrians or vehicles, and the safety of the surrounding vehicles and pedestrians and driving of the unmanned vehicle is guaranteed.