For preventing traffic accidents, research on non-instrument wearable driver fatigue identification method based on surface pressure sensor is researched. A test for obtaining the pressure signals through surface pressure sensor mounted on the back of the driver's seat is designed, the time domain signals is processed in frequency domain, then the coherence function of the ECG signal and the surface pressure signal is calculated, the conclusion of the correlation between ECG signal and surface pressure signal is verified. Then, the noise reduction of ECG signal and data processing and data modifying of HRV were verified. The conclusion is the same as the LF value of the heart rate variability signal. The results show that the surface pressure sensor is correct for fatigue driving detection.