The utility model relates to a dielectric isolation packaging structure for a pressure sensor. The dielectric isolation packaging structure for the pressure sensor comprises a plastic substrate, an isolation diaphragm, a plastic tubular shell and a sensitive element, wherein the plastic substrate is provided with a bottom plate and an opening end which are arranged in an opposite manner, and the bottom plate is provided with a through hole; the isolation diaphragm seals the opening end of the plastic substrate; the plastic tubular shell is arranged on the bottom plate of the plastic substrate; and the sensitive element is arranged in the plastic tubular shell, the sensitive element is provided with a back cavity, the back cavity faces the through hole of the plastic substrate, and the plastic substrate, the sensitive element and the isolation diaphragm form a sealed cavity filled with an isolation dielectric together. According to the utility model, the isolation diaphragm is arranged on the plastic substrate, the sensitive element is arranged in the plastic tubular shell, and the plastic substrate, the sensitive element and the isolation diaphragm form the sealed cavity filled with the isolation dielectric together, so that the dielectric isolation packaging structure for the pressure sensor is small in size and convenient to installed, compared with the existing isolation technology; in addition, different from the packaging technology in which stainless steel is adopted for silicone oil filling, the dielectric isolation packaging structure for the pressure sensor uses the plastic substrate and the plastic tubular shell, so that the cost is low.