1. A coherent Ising machine based on on-chip whispering gallery mode optical microcavity, wherein the coherent Ising machine comprises: a laser emitter, wherein the laser emitter is used to emit a first pulse laser with a first wavelength; a first laser processing apparatus, wherein the first laser processing apparatus is configured to convert the first pulse laser to a second pulse laser with a second wavelength; an optical microcavity, wherein the optical microcavity has a resonant cavity of a rotational symmetrical structure and is configured to allow an optical field to undergo total reflection on an inner surface of the resonant cavity, a second laser processing apparatus is integrated in the optical microcavity, the second laser processing apparatus is configured to convert the second pulse laser injected into the optical microcavity to a third pulse laser with the first wavelength, and the second laser processing apparatus is integrated at a coupling end of the optical microcavity; a zero-beat frequency measurement apparatus, wherein the zero-beat frequency measurement apparatus is configured to obtain a phase of the third pulse laser according to the first pulse laser and the third pulse laser; and a feedback apparatus, wherein the feedback apparatus is configured to adjust an amplitude and phase of the first pulse laser according to the phase of the third pulse laser, and complete injection into the optical microcavity at a preset time point, to enhance the third pulse laser; and a first coupler, wherein the first coupler is configured to inject the second pulse laser into the optical microcavity via an upper waveguide configured in the optical microcavity; wherein the first coupler is also used to inject a first pulse signal processed by the feedback apparatus into the optical microcavity via the upper waveguide; or, a lower waveguide is configured in the optical microcavity, and the first pulse signal processed by the feedback apparatus is injected into the optical microcavity via the lower waveguide.