It is very important for oil and gas field exploration and development to accurately obtain reservoir permeability. SDR model and Coates model based on NMR are the most accurate classical models for reservoir permeability calculation at present. The classical SDR model and Coates model have achieved very good results in actual production, but have poor application effect in overpressure reservoir, and there is a large error between calculated permeability and core analysis permeability. Overpressure conglomerate reservoir has the abnormal characteristics of low porosity and high permeability, and the classical model of permeability calculation by NMR logging can not calculate the reservoir permeability. By analyzing the characteristics of overpressure reservoir and the influencing mechanism on physical properties, it is clear that overpressure intensity is the main controlling factor of permeability. A new method of constructing NMR permeability processing model of overpressure conglomerate reservoir by introducing overpressure physical property index and pore structure index based on SDR model is proposed. Taking the Permian Upper Wuerhe Formation in Mahu sag of Junggar Basin as an example, the petrophysical joint test of overpressured conglomerate reservoir is carried out to simulate overpressure. The effects of overpressure on porosity, permeability and resistivity of reservoir is studied, and the SDR overpressure permeability calculation model of overpressure conglomerate reservoir is established. Compared with core analysis data, the new model has achieved good results in reservoir permeability calculation.