The invention belongs to the field of non-classical optical fields, and discloses a quasi-continuous quantum compression vacuum state optical field generating device which comprises a laser, an optical parametric amplifier, a detection module and a scanning locking module, wherein the optical parametric amplifier comprises an OPO cavity, a first phase shifter and a second phase shifter; seed lightemitted by the laser is incident to the OPO cavity to generate compressed light, a cavity front reflection signal of the OPO cavity is detected by a first detector, pump light emitted by the laser isincident to the OPO cavity after passing through the first phase shifter, and the pump light and the compressed light emitted from the OPO cavity are detected by a second detector; background light emitted by the laser is combined with compressed light emitted by the OPO cavity through a beam splitter after passing through the second phase shifter, and then is detected by a balanced zero-beat detector; the scanning locking module is used for locking the phase of the OPO cavity length, the pumping light and the seed light and the phase of the compressed light and the background light. The quasi-continuous quantum compression vacuum state optical field generating device can stably operate and generate a quasi-continuous compressed vacuum state optical field with a compression degree higherthan 10 dB.