The invention relates to the technical field of pressure sensors, and discloses an MEMS pressure sensor oil filling core which comprises an upper cover, a base and a sensitive assembly. A lower end ofthe upper cover is in sealed connection with the base, the base and the upper cover form a sealed cavity, and the sealed cavity is filled with a detection medium; a sensitive assembly is arranged onthe base and located in the sealed cavity. According to the MEMS pressure sensor oil-filled core and the packaging method thereof, a chip composed of a silicon elastic diaphragm, a semiconductor resistor and signal calibration modules is adopted; a signal processing circuit does not need to be arranged outside, and lead wire interconnection is reduced; the structure is simple, the cost is low, theproduct reliability is high, and convenience of production is achieved; the semiconductor resistor and the signal calibration module are located on different planes, the signal calibration modules are located on the periphery of the silicon elastic diaphragm, the risk that lines in the signal calibration module are damaged due to the fact that stress changes of the silicon elastic diaphragm influence the signal calibration module is prevented, and precision can be guaranteed.