The invention discloses a driving warning steering wheel cover device based on psychological and physiological signals and a signal detection method. The device comprises a signal detection module, a data transmission module and a data processing module; a sensor in the signal detection module detects the psychological and physiological signals of a driver according to the two hands, placing on a steering wheel, of the driver and transmits the collected psychological and physiological signals to the data transmission module, the data transmission module transmits the psychological and physiological signals to the data processing module, and the data processing module stores, analyzes and early warns received signal data. Meanwhile, the invention provides a method for detecting abnormal states. The method comprises the steps that a self-adaptive neural network is constructed, a difference between the current driving state and a normal state is judged in real time, abnormal values are identified in real time, and a grading early warning decision is made according to an error value. The device is high in practicability, strange in assisted data judging and high in accuracy, detection result reliability and intelligence.