The invention relates to a deepwater beacon searching and positioning method suitable for a single hydrophone, which employs a single-element hydrophone to receive signals emitted by an underwater beacon, and comprises: in a period when a receiving point moves from A1 to A2, calculating an acoustic propagation distance in a period of the pulse separation variable quantity of beacon echo signals; in a period when a receiving point moves from A1 to A3, calculating an acoustic propagation distance in a period of the pulse separation variable quantity of beacon echo signals; and calculating the position of the underwater beacon.