The invention discloses a method for detecting a 
parking space through double barrels. The method comprises: 1, a 
vehicle driving into the 
parking space; 2, a geomagnetic sensor in a 
parking space detector II sensing the change of a 
magnetic field, and when the change of the 
magnetic field reaches a preset change threshold value, starting 125KHZ 
wireless signals to be transmitted; 3, the parking space 
detector I being awakened by a 125KHZ 
wireless signal transmitted by the parking space 
detector II and enters a receiving mode; 4, the parking space detector I judging whether the data is sent bythe parking space detector II or not according to the received data; 5, if so, taking out a received 
signal intensity value, and judging the state of the parking space according to a trigger threshold value; and 6, if not, continuing to enter a low-power-consumption interception state, and ending. The double-
barrel parking space detection technology, the 
radar technology, the 
ultrasonic technology and the like have the advantages that the frequency is low, the penetrability is good, and 125Khz 
wireless radio frequency signals can be suitable for 
severe weather such as rain and 
snow, so that the problem of low parking space detection accuracy under the condition of 
severe weather such as rain and 
snow is solved.