An abnormal condition identification method for the tire pressure of a goods wagon belongs to the technical field of secure state detection of an automobile. The abnormal condition identification method comprises the steps as follows: a tire state data base comprising tire models, the relation between load and initial inflation pressure, real-time tire pressure, load, vehicle speed and external environmental temperature is created; frequency is acquired on the basis of set data so as to measure tire state parameters which are then input to the tire state data base in an industrial computer; the prewarning threshold value of the abnormal condition identification of the tire pressure is confirmed on the basis of a test on the relation between the rolling tire pressure and influence factors thereof; in addition, data processing programs of the abnormal condition identification of the tire pressure are written, and the tire pressure states of start-up, parking and driving of the automobile can be monitored and prewarned respectively. The abnormal condition identification method effectively solves the difficult problem that the prewarning threshold value of the rolling tire pressure varies with the changes of working conditions, can greatly reduce the probability of misinformation and omission, improves the prewarning accuracy of the abnormal condition of the tire pressure, and canprovide the theory basis for the setting of prewarning regulations of a tire pressure monitoring prewarning system at the same time.