The invention discloses a receiving and transmitting integrated inverse SAL (synthetic aperture ladar) system based on an acousto-optic frequency shifter. A laser beam emitted by a laser is split by a polarizing beam splitter, a first beam passes through a first cube-corner prism, a fiber bragg grating, a first beam splitter prism, a 1/4 wave plate, a first diaphragm and a telescopic system, is irradiated to a target and then reflected back to reach the first beam splitter prism and is reflected to a second beam splitter prism to be divided into two beams; a second beam passes through the acousto-optic frequency shifter, a second cube-corner prism and the second beam splitter prism and is divided into two beams; the two beams of the first beam and the two beams of the second beam pass through a second diaphragm, a third diaphragm, a polarization analyzer I, a photoelectric detector I, a polarization analyzer II and a photoelectric detector II respectively and two generated electric signals pass through a pre-amplifier, a frequency mixer and a signal processor for processing. The receiving and transmitting integrated inverse SAL system adopts receiving and transmitting integrated overall design, the signal to noise ratio is increased, and the resolution ratio is increased.