Abstract: In order to detect freezing of gait of Parkinson's patients automatically, a system based on inertial measurement unit to detect freezing of gait for Parkinson's patients is established. The two inertial measurement units are respectively fixed on the left and right ankles of the patient to be measured, the freezing index is calculated by windowed Fourier transform, the freezing threshold is calculated based on the freezing index during normal walking, and the freezing index and the freezing threshold are compared to complete the detection of freezing of gait. The experimental results show that the number of freezing of gait occurrences in Parkinson's patients is accurately detected, and it has high sensitivity and specificity, which can assist doctors to objectively assess the patient's condition.