Negative pressure structure of non-liquid-return water light needle

The utility model discloses a liquid-return-free hydro-optical needle negative pressure structure, which belongs to the technical field of hydro-optical needles and comprises a negative pressure cavity, a plurality of injection needles, a communicating pipe, a filter component and an air pipe. The filter assembly comprises a filter chamber, a filter element and a drainage connector, the filter chamber is communicated with the negative pressure cavity through a communicating pipe, the air pipe is communicated with the negative pressure cavity through the filter chamber, and the filter element is installed in the filter chamber to filter liquid or oil dirt entering from the negative pressure cavity and prevent the liquid or oil dirt from entering the air pipe. The drainage connector is detachably connected with the liquid outlet, and when the drainage connector is separated from the liquid outlet, liquid or oil dirt is discharged out of the liquid outlet and prevented from entering the air pipe to pollute compo